Gh Problem

[dale_d_h]

Ive just been out and bought a NUTRAFIN MASTER TEST KIT
Here are my results:

190 litre tank:
Ph - 7.2
Ammonia - 0.1 mg/l
Nitrite - 0 mg/l
Nitrate - 110 mg/l
Phosphate - 5 mg/l
Kh - 60 mg/l
Gh - 520 mg/l
Ca - 200 mg/l


High nitrite and phosphate so a 30 litre water change was done right away, then another tomorrow


250 litre tank:
Ph - 7.2
Ammonia - 0.1 mg/l
Nitrite - 0 mg/l
Nitrate - 50 mg/l
Phosphate - 5 mg/l
Kh - 50 mg/l
Gh - 560 mg/l
Ca - 260 mg/l

High phosphate again, cut down on feeding will fix that. 30 litre water change


Ok, here is the one that has really got me scratching my head.

180 litre Brackish tank:
sg - 1.009 (normally held near around 1.010-1.012)
Ph - 8.1
Ammonia - 0 mg/l
Nitrite - 0 mg/l
Nitrate - 50 mg/l
Phosphate - 5 mg/l
Kh - 120 mg/l
Ca - 400 mg/l

Gh - this test is done by adding 1 drop until the water goes from pink to purple then multiply that by 20. I gave up after 70 drops! Cleaned out a new test tube (with fresh water only) and started again. Once again got to 40 drops and thought there is something wrong here!!! It is a hard water area as the other results show from the other tanks, but as high as that result would of shown over 1400 mg/l? Any ideas?

 

[CFC]

I'm going to move this to the scientific forum as you may be able to get better answers there.

 

[monkey_biz]

in all your tanks the general hardness is highish. GA and KH are the measure of of how much stuff is dissolved in it added all together its called TDS, or total dissolved solids. water can only hold so much at which point it becomes saturated.

could you describe your tank... ie filters substrate ornaments (stone type only) bogwood ect
then test your tap water and post that
then any addative you put in ect

in brackish water you add salt, if you have tuffa rock bogwood and crushed coral substrate all this increases the TDS and if your tap water is already high it could explain it

but more info is required

 

[andywg]

GH is closely associated with TDS (total dissolved solids). To make brackish water you are dissolving large amounts of solids (salt) into water. Therefore your GH on a salt tank will be very high. For this reason marine aquarists seldom bother with GH as it tells them nothing useful. We know the GH is going to be high, that's because we are dissolving large amounts of salt in our water.

 

[monkey_biz]

yes but in a brackish tank we are only talking about smal amounts of salt and not enough to give a reading of over 1400ppl. that is saturated!
it points towards the supply water especially the phosphate level

 

[andywg]

yes but in a brackish tank we are only talking about smal amounts of salt and not enough to give a reading of over 1400ppl. that is saturated!
it points towards the supply water especially the phosphate level

Ok, GH is a measurement of calcium and magnesium ions in the water. 1.009 is going to be about 41% of sea water, that's not a small amount.

The tank already has 400 mg/l showing form the calcium. In marine chemistry one will usually find magnesium levels in the region of 2-2.5 times as high as calcium. This will give us enough magnesium to get to 1,400 mg/l.

What does interest me is that water with such a low salinity is capable of experiencing such high calcium levels. Many people with full strength marine tanks struggle to get their calcium up that high.

In this instance I would be looking at the test kits as being potentially a problem.

As to water being saturated at 1,400 ppl (first time I can recall seeing parts per litre) I am not so sure. My reef water contains 450ppm calcium, 1,300 ppm magnesium and as it has 35ppt salinity, somewhere in the order of 35,000 ppm of sodium and chloride. Sodium and Chloride account for roughly 75-80% of the contents of a marine salt mix, meaning that my water has dissolved in it at least 42,000ppm. This would imply to me that even with a GH level of 1,400ppm, there is still a fair amount of room for further solids to dissolve into a tank. I know this because I dissolve additives to maintain a higher KH and calcium than my salt mix supply.

 

[monkey_biz]

oops meant mg/l ie ppm.... me is bad
i meant it was a higher salt content than it measured, ie seemed to much salt for brackish, poor choise of words on my part
ok i see where where you are comming from, makes sense now written that way, didnt realise there was a multiplying relationship between calcium and magnesium ion.
my logic was the ammount of sodium ion but i was in error as the sodium ion would actually reduce the Gh so ignoreme im having a blond moment

 

[andywg]

oops meant mg/l ie ppm.... me is bad

Not necessarily. One can have ppl, just it isn't commonly used. In this context, where ppm is broadly equal to mg/l it makes no great odds.

i meant it was a higher salt content than it measured, ie seemed to much salt for brackish, poor choise of words on my part
ok i see where where you are comming from, makes sense now written that way, didnt realise there was a multiplying relationship between calcium and magnesium ion.
my logic was the ammount of sodium ion but i was in error as the sodium ion would actually reduce the Gh so ignoreme im having a blond moment

To be honest, it does still appear that something is affecting the water chemistry. Note my comment on calcium. There are some people that can't get levels like that with a full marine mix, getting it with 41% of the salt would usually imply that something is affecting either the water, or the test.

 

[monkey_biz]

im used to dealing with a couple of hundred meters cubed of water so i tend to work with litres and not milligrams so its bad on my part otherwise ill do it again and some tank somewhere will have a kilo of bicarb added

anyway..................... good possibility is source water or a duff kit. id lean to the source water and ornaments in the tank.
could be hard water + salt mix + tuffa/coral/coral sand/limestone in filters and tank.

still need more info and a test on tap water or a location and i can get the average local water board readings from my manual

 

[waterdrop]

GH is closely associated with TDS (total dissolved solids). To make brackish water you are dissolving large amounts of solids (salt) into water. Therefore your GH on a salt tank will be very high. For this reason marine aquarists seldom bother with GH as it tells them nothing useful. We know the GH is going to be high, that's because we are dissolving large amounts of salt in our water.

What's the difference between GH and TDS (total dissolved solids?)

 

[andywg]

What's the difference between GH and TDS (total dissolved solids?)

GH is a measurement of Calcium and Magnesium ions dissolved in the water. TDS is (as the name suggests) a measurement of everything dissolved in the water. It is most commonly used on RO or RO/DI water to make sure that the membrane still functions.

 

[monkey_biz]

hmmmm, my books are vague when it comes to the states. all it says is north carolina has radon 222 and high nitrate levels as well as a average TDS of 100-300
hmmmm, bugger the tds level id worry more about your radon level

if your tap TDS is say 300, add up your other readings in your FW tanks take the 300 from the total and you will find your average reading is about normal, add salt then its close to being normal for the brackish tank. what is normal anyway???

are you on public water supply or well?? could be time for a RO unit if you are really bothered. are your fish healthy?? have they been in the tank for a long time are they thriving??? if so leave and accept it

 

[waterdrop]

What's the difference between GH and TDS (total dissolved solids?)

GH is a measurement of Calcium and Magnesium ions dissolved in the water. TDS is (as the name suggests) a measurement of everything dissolved in the water. It is most commonly used on RO or RO/DI water to make sure that the membrane still functions.

thx andy! I'd love it if you'd comment on my "best practices" thread nearby

hmmmm, my books are vague when it comes to the states. all it says is north carolina has radon 222 and high nitrate levels as well as a average TDS of 100-300
hmmmm, bugger the tds level id worry more about your radon level

if your tap TDS is say 300, add up your other readings in your FW tanks take the 300 from the total and you will find your average reading is about normal, add salt then its close to being normal for the brackish tank. what is normal anyway???

are you on public water supply or well?? could be time for a RO unit if you are really bothered. are your fish healthy?? have they been in the tank for a long time are they thriving??? if so leave and accept it

thanks monkey, lol, I've got no real problems, I haven't even got any fish! I'm just interested in the theory, thus the reason for starting a thread in the scientific section.

Radon is indeed a problem here and there in NC, it happens is small pockets and I happen not to be in one thankfully.

~~waterdrop~~