Increasing Water Hardness - Gh

[rust81]

My tank is only showing 1-2 degrees of general hardness (GH) which is fine for discus but not for the fish I keep! I have mollies, bristlenose (which need a minimum of 4 degrees) and clown loaches. My problem stems from using too much RO water and not re-mineralising the water. Has anyone got any tips for products that can raise the hardness. My tap water is around 6-7 dGH but I can't do 100% water change obviously, but I need to start increasing the dGH. Thanks

 

[Zikofski]

firstly my tap water is GH 0 >_< i have BN, CPD and rasbora they all seem fine altho i dose EI and i do dose Magnesium Sulhpate which i believe has increased my GH slightly i am not sure to what but i think it is in the region of 4 or 5, i shall test tomorrow when i can to find out but i put 5/8th as per my EI fertiliser dosing for plants, but if your tap water is 6-7 just do as close to 100% wc as u can and it will be fine, over time with WC from your tap it will level out to 6-7 from your tap if u still want to use RO water then maybe looking at what is needed to increase the GH officially not sure if my way is the correct way or not >_<

 

[Byron]

My tank is only showing 1-2 degrees of general hardness (GH) which is fine for discus but not for the fish I keep! I have mollies, bristlenose (which need a minimum of 4 degrees) and clown loaches. My problem stems from using too much RO water and not re-mineralising the water. Has anyone got any tips for products that can raise the hardness. My tap water is around 6-7 dGH but I can't do 100% water change obviously, but I need to start increasing the dGH. Thanks

Is there a reason you have been using RO water up to now?  Tap water with 6-7 dGH is not going to cause problems for the soft water fish you mention (clown loach, bristlenose) though the mollies need more than this to be at their best.  Mollies are prone to skin problems, shimmying, fungus, etc. in soft water, and 6 dGH is still "soft."
 
Can you separate the mollies from the others?  This would allow you to increase the GH (and corresponding pH) quite a bit which would benefit them.  But if separation is not feasible, not to worry, because you can still raise the GH to help the moliies without hurting the loaches.  A GH around 12 dGH would be fine.
 
Raising GH for plants and for fish is rather two different issues.  I have near-zero GH in my tap water which is fine for my soft water fish [I just do not consider livebearers and other fish requiring moderately hard or harder water, makes things much simpler] but provides insufficient hard minerals especially calcium for some plants.  Echinodorus and Helanthium are especially affected.  A GH of 4 to 5 as Zikofski mentioned is sufficient for most plants.  I use Equilibrium to achieve this as it easily gives me a balanced hard mineral supplement without affecting pH.  But here we are talking fish needs, and this is a different thing.
 
For that, I prefer using a crushed coral/aragonite or dolomite substrate material.  This can be added to the filter (if a canister) or used as part of the substrate.  I would only do the latter if hard water fish alone are in the aquarium, as this can raise the GH and pH significantly, and there is no point in making life difficult for soft water fish.
 
There are also preparations you can buy to achieve this.  Most costly long-term, but again if you intend keeping the mix of fish it may be better to go this route as the intended GH should be more easily managed.
 
Hope this helps, but don't hesitate to ask further.
 
Byron.

 

[rust81]

So I've been doing 15% water changes every other day to slowly increase the GH in my tank. On Tuesday my tank was reading about 4 GH after I'd finished a water change. I tested again last night and it's dropped back to 2 GH. On top of the fish that I have I have a sand substrate, lots of live plants, a small piece of bogwood and the normal t5 lighting which is a good few years old. What could be causing my GH to drop. My understanding was GH is made up of magnesium and calcium ions in the water. So I I'm not removing these how can the GH drop from 4 to 2? Any ideas?

 

[TwoTankAmin]

Both of those things can get used up in a tank. Bear in mind that to make bones and shells it requires calcium among other things and plants will use some as well. Most people who need to monitor their water hardenss do not rely on GH or KH as neither of these is really all there is that contributes to these things. Instead they rely on more comprehensive means.
 
The first thing o understand about pure water is that it contain H and O and that is it. And then one needs to understand that pure water is a lousy conductor of electricity. What turns it into the puddle you don't want to stand in are all the solids that get dissolved in the water- hence one measure being called Today Dissolved Solids - aka TDS. These are actually measured by a device called a conductivity meter. What this does is send a small current between two electrodes and measures how well the water conducts this charge between the two. The more stuff there is in the water the better conductor it becomes.
 
TDS consists of anything that contributes to GH and to KH as well all ions and other things that are involved. For example, salt doesn't affect hardness or alkalinity but it does affect conductivity and TDS. In most cases it is enough for hobbyists to measure GH and KH, but for more sophisticated applications one must turn to the more accurate conductivity or TDS  meters. An example is breeding fish which are seasonal spawners where one needs to change these parameters to replicate the natural changes to the water that come from the cycle of dry and rainy season each year.
 
I use RO/DI water and usually mix it 50/50 with my tap. If one has really nasty tap and cannot do this, then you do need to do something like Byron mentioned and add back the needed minerals and trace elements. That is why we fw folks who need to treat fish using salt can rely on plain old table salt but the sw folks seeking to create sw in tanks must use a salt mix which also contains the other needed elements found in sea water- this is more than just plain salt.

 

[rust81]

Thanks for the info twotankadmin - very useful indeed. I'm still puzzled as to how the GH could drop so much (from 4 to 2) when I don't have any snails, not that many fish but quite a few plants. Could the plants make the GH move that much? I'm going to get some seachem equilibrium over the weekend and try and increase the GH upto 6 slowly.

 

[TwoTankAmin]

This may help as well:
 

Altering Your Water's Chemistry
 
Hardening Your Water (Raising GH and/or KH)
 
The following measurements are approximate; use a test kit to verify you've achieved the intended results. Note that if your water is extremely soft to begin with (1 degree KH or less), you may get a drastic change in pH as the buffer is added.
 
To raise both GH and KH simultaneously, add calcium carbonate (CaCO3). 1/2 teaspoon per 100 liters of water will increase both the KH and GH by about 1-2 dH. Alternatively, add some sea shells, coral, limestone, marble chips, etc. to your filter.
 
To raise the KH without raising the GH, add sodium bicarbonate (NaHCO3), commonly known as baking soda. 1/2 teaspoon per 100 Liters raises the KH by about 1 dH. Sodium bicarbonate drives the pH towards an equilibrium value of 8.2.

from http/fins.actwin.com/mirror/begin-chem.html

 

[Byron]

TwoTank has given a very good explanation of the TD/GH issue (post #5) and raising GH/KH (post #7) is true, but your initial question remains, and frankly, I am at a loss to provide an answer as to how your GH could be dropping as much as it is.  I have to honestly say that this seems almost impossible from the data we have been given.  
 
Which test kit are you using for the GH tests?  According to the online data, the API GH test measures calcium and magnesium, the two mineral salts primarily responsible for what we term general hardness.  Other minerals like iron, potassium, etc can impact GH as well, but even if these were present in your water I would not expect the system's use of all of them to be as great as this.
 
In my own experience, I have near-zero GH in my tap water; the actual amount according to the water folks is 7-8 ppm, which is less than 1 dGH, and using the API liquid test it turns green with one drop so this is in sync.  In three of my six current tanks I leave the GH alone, and in the other three I raise the GH solely for the benefit of the plants.  Calcium deficiency occurs with the Echinodorus, Aponogeton and Tiger Lotus plants so I use Equilibrium to raise the GH to somewhere between 4 and 6 dGH.  I carried out tests for about six weeks on these three tanks to determine the extent of the plant's use of GH, and to my surprise there was no change.  Now, the API test is obviously not scientifically accurate to the extent that one can measure small deviations, but I had expected to see the GH lower at least by 1 over a period of a week, but it doesn't.  To give one example, Equilibrium is added sufficient to raise the GH from 1 dGH to 6 dGH.  The test immediately prior to the following week's water change indicates 6 dGH; immediately after a 50% water change the GH is 3 dGH as one would expect; Equilibrium is added and the following morning it is again 6 dGH, where it remains for the week until the next water change.  The plants are clearly using calcium particularly, as without the Equilibrium they develop signs of severe calcium deficiency within a couple weeks, and maintaining the afore-mentioned dosage keeps them bright and green.
 
My tanks are fairly heavily planted, including a good cover of fast-growing surface plants like Water Sprite, Pennywort, Frogbit, and Water Lettuce, and the fish loads cannot be deemed light; yet there is no discernible drop in GH according to the API test.  The tanks also have considerable quantities of wood, and even dried leaves in one.  Coming back to your situation, a drop of 2 dGH and even more is puzzling to me.  I'd be interested in finding out just what is happening here.
 
By the way, on the subject of buffering, one has to be very careful.  As the data cited in post #7 mentions, a drastic rise in pH can occur, and this can cause serious issues for many soft water fish.  This is why I use Equilibrium; it does not affect pH, so in my tanks it remains in the low 6's.  Another point is that baking soda (sodium bicarbonate) is not a good additive.  Stanley Weitzman discussed this in an article on preparing suitable water to spawn soft water fish, and mentioned that it has no long-term buffering capacity, so eventually the organic build-up overpowers the buffering.  In addition, the sodium this adds is certainly not good for soft water fish, quite the opposite.  Messing with water chemistry can be tricky.
 
Byron.

 

[TwoTankAmin]

Lets consider the chemistry and the above directions and you get an interesting result.
 
Start with 1/2 teaspoon to raise the KH by 1 dh in about 26 gallons of water (110l/3.8).
 
Then consider the molecular weight of NaHCO3.
 
Element Symbol Atomic Mass # of Atoms Mass Percent Sodium Na 22.989770 1 27.367% Hydrogen H 1.00794 1 1.200% Carbon C 12.0107 1 14.297% Oxygen O 15.9994 3 57.136%
 
This means, if you add 1 teaspoon to 52 gals., you are adding about 1/4 teaspoon of sodium. Considering that all animals need sodium and some plants will use it as well and then that one tends to change water regularly. I am not sure how much of a sodium buildup there might be in an aquarium unless one were adding large amounts of Sodium Bicarb.
 
While I agree about not using sodium bicarbonate for soft water fish, it is a standard component in African cichlid salt mixes. Here is a recipe from Wet Web Media:

A Simple But Effective Rift Valley Cichlid Salt Mix (but it's good for Central American cichlids, livebearers, goldfish and community fish too!)

You can buy cichlid salt mixes from aquarium shops, but you can make your own very inexpensively. You'll need baking soda and Epsom salt, which you can get from most grocery or drug stores, and marine salt mix, which your aquarium shop will have. Note that marine salt mix isn't the same thing as "aquarium salt" or "tonic salt"; you want to buy the stuff used in marine aquaria. If in doubt, ask your retailer for salt to use in a marine aquarium. Common brands include Reef Crystals, Instant Ocean and so on. For our purposes, all are good, so get whatever is cheapest.

Per 5 US gallons (20 litres) add the following amounts of each ingredient:

* 1 teaspoon baking soda (sodium bicarbonate)
* 1 tablespoon Epsom salt (magnesium sulfate)
* 1 teaspoon marine salt mix (sodium chloride + trace elements)

from http/www.wetwebmedia.com/fwsubwebindex/fwh2oquality.htm
 
That recipe uses 5 times the sodium bicarb as the amount given on the FINS site for raising KH by 1 dg. So it is clear that this ingredient does not build up to harmful levels for these fish. This is what makes this hobby so dang interesting, so much variability and variety and so few universals.
 
My preference is to put a bag of crushed coral in a filter to help with KH. I have found in smaller amounts like these it will raise the KH from the carbonate but the difficulty in dissolving the calcium part keeps the GH from rising much. When I was messing around with ways of doing dry and rainy seasons I tried to avoid buying an ro unit by raising the hardness in a tank and then using my tap to reverse it. I would start by running a H.O.T Magnum filled with crushed coral on the new water for a day. the TDS rose by about 20 ppm. To move it the rest of the way from my tap's 80 ppm to my target of 160 ppm took a few tablespoons of Epsom salt and a pinch of baking soda (not enough to affect the pH by more than .1). The crushed coral was the least effective means for raising the TDS.
 
As an interesting aside, in doing research on nitrite and fish I ran across an interesting study. They exposed two different species of fw fish to nitrite to determine how it affected them. One of the things they noted during the study was that as levels of nitrite rose, the level of sodium inside the fish decreased.

 

[rust81]

I'm also thinking that the API test kit I have may be providing incorrect results. According to the water board my GH should be 6-8, but when I tested the tap water again this morning it was 4. I live in a Victorian house that still has some lead pipe work but still that shouldn't make a difference. If anything wouldn't it increased the GH if it is adding to the metal ions.

My original reason for sorting out the hardness was to support the bristlenose plecs that I have. I posted a discussion in the emergency section a few weeks ago as my plecs were hanging out near the top of the tank, not eating and not moving much. I tested the water parameters and all were fine. No visible signs on any of the plecs or their tank mates. It was my friend who is a qualified marine biologist that mentioned the calcium needed by plecs and he asked whether I was re mineralising my RO water. To date I've been trying to sort out GH , but should I be looking at Kh if that is the calcium component.

Thanks

 

[TwoTankAmin]

Drats the chart I pasted above fell apart:
 
Element  Symbol     Atomic Mass       # of Atoms      Mass Percent
Sodium       Na            22.989770                   1                27.367%
Hydrogen    H                1.00794                     1                  1.200%
Carbon        C              12.0107                       1                14.297%
Oxygen       O              15.9994                       3                57.136%
 
 
But to go back to the beginning of all this, why do you not mix your tap and ro? RO has almost no GH or KH.
 
You have 0 with the RO, you change 15% of the water and replace it with your tap and how much "GH" does this add? 15% of 7-8 is 1.1-1.2 GH. But it is not quite that simple as has been stated above. However, I do not really see how a 15% change gets to be 4 dg considering the water was starved for the needed elements and some surely would have been taken up fairly quickly?
 
You state you realize you cannot do big water changes because it would raise things too fast and then asked for a chemical means to raise it?  There is little difference between these two methods. An "additive" is just a dry version of what is in your tap. Since 15% isn't cutting it, how about doing larger water changes, say 25%? And if that doesn't do the trick, increase that to 35%. Incidentally, the fertilizers you should be dosing for your plants should be contributing to GH. Can you report what your are adding in this respect and how often?

 

[rust81]

I've done about 4 15% water changes over the past 10 days which is how I got up to about 4 GH. But as mentioned when I took the GH reading the other day the GH had dropped to 2 somehow. I don't add anything for my plants - I just have the lights on for 8 hrs per day. I only have amazon swords, anubais and some java fern.

Just checked the water boards stats and they are as follows:
70 mg/l Ca
175 mg/l CaCO3
This equates to 9.8 German degrees, which I assume is 9.8 GH

TDS is 284ppm

 

[TwoTankAmin]

OK yo give you an idea, my tap water TDS is 83 ppm in normal times and I have seen it as low as 57 ppm after prolonged heavy rains. When I began in this hobby it was wa bout 106 ppm (an estimate as then I had no digital meters/monitors).
 
Right now I have about 100 bn I do not want. I have had about 1,000 born in my tanks over the past 12 or so years.
 
Bear in mind what GH kits in the hobby read:

 
General hardness (GH) refers to the dissolved concentration of magnesium and calcium ions. When fish are said to prefer ``soft'' or ``hard'' water, it is GH (not KH) that is being referred to.............                Water hardness follows the following guidelines. The unit dH means ``degree hardness'', while ppm means ``parts per million'', which is roughly equivalent to mg/L in water. 1 unit dH equals 17.8 ppm CaCO3. Most test kits give the hardness in units of CaCO3; this means the hardness is equivalent to that much CaCO3 in water but does not mean it actually came from CaCO3.

from http/fins.actwin.com/mirror/begin-chem.html
 
I would suggest, and I think Byron would concur, that you should be adding something for your plants. I keep, or have kept, all three of those plants and at the very least I add trace elements and micronutrients for them weekly and have always used a substrate fertilizer for swords.
 

 

[Byron]

I'll try to pick up on a couple points mentioned in recent posts.
 
First is on the GH for Bristlenose.  The exact species sold in stores is unknown unless the fish is wild caught or obtained from a breeder who knows the species.  There are 64 species (according to Fishbase) in the genus Ancistrus, occurring all over the Amazon floodplain in various water habitats.  The common Bristlenose is thought by some ichthyologists to possibly be a hybrid of other species, and there are of course the further man-made hybrids such as the albino and long-fin, neither of which exist in the wild.  Many of the wild species obviously occur in water with no detectable calcium to speak of, so they must fill their calcium needs via food.  Ancistrus sp are omnivorous but primarily vegetarian, and there is calcium in plant matter and algae, but they also eat crustaceans which occur in all (as far as I know) watercourses in the Amazon and minutely in the biofilm aufwuchs that these fish graze.  If the GH gets stabilized around 4 or 5 dGH, it will be sufficient for the plants, and for the Bristlenose according to your biologist.
 
To the plants and fertilizer.  Echinodorus sp. (the "Amazon swords") are heavy feeders.  I have had several natural and a few hybrid species of these plants in my tanks for well over 20 years.  I have very soft water so plant nutrients must be supplemented, as there is simply not sufficient in fish foods to provide what these plants require.  A basic liquid complete fertilizer will usually suffice (except in very soft water as these liquids do not have sufficient hard minerals to compensate), though the larger swords will not be as vigorous but they will manage.  Adding substrate fertilizers in addition to the liquid is advisable.  Aquatic plants take up some nutrients primarily if not exclusively via the leaves, and of course all nutrients have to be dispersed into the water column before they can be assimilated via leaves or roots, so a complete liquid is the first step.  I use Seachem's Flourish Comprehensive Supplement once a week, plus their Flourish Tabs (one next to each large sword, replaced every three months).  The benefit of the substrate tabs is getting more nutrients close to the roots, and these nutrients do not leech into the water column above which can feed algae, so the plants benefit but algae does not.  I also use Flourish Trace, and started this when I stopped the second weekly dose of Flourish Comprehensive, as a trial, and I have found that the plants are doing the same (perhaps a tad better, the floating anyway) but algae is much less apparent.  The attached photo shows the results of this method (and I do not use CO2, only natural from the substrate organics), this is my 115g Amazon riverscape which has the largest sword species.  
 
A GH of 4 dGH or 70 ppm is said to be sufficient for plants, and I keep my three largest tanks (having these species) around 5 dGH and it has proven sufficient.  I use Equilibrium to achieve this as it adds the minerals but does not mess with pH.  I tried crushed coral/aragonite but even as minimal amount as half a cup in the filter in the 115g sent the pH soaring to 7.6 so that was quickly removed.  This tank is stable around 6.2 to 6.4 on its own.

 

[rust81]

Byron, your tank looks great. I've taken your advice and bought some seachem plant ferts and also some seachem stability to raise the GH in the RO water. Tank looking ok so far and tank mates happy.