Help with pH during fishless cycle

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james_fish

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Hello everyone;

I'm 21 days into a fishless cycle in a 200 litre tank, and things to seem to be going extremely well.
Yesterday I added 3ppm of liquid ammonia and todays results showed 0 ammonia and 0 nitrite which is very promising after 21 days.

However,

I'm having some extreme difficulty maintaining a constant pH level.
for the first 8 days or so my tank stayed at around 6.8 pH which was fine, I can live with that.
However shortly after it crashed to 6.0 (or below) - so naturally, I acted straight away by doing a water change of about 40% to try and pump it back up a little, 24h later it hadn't worked. So I added 3 teaspoons of bicarbonate soda, this did work - I got it up to 7.6. This is higher than what I'll want when I add fish (south american community) but fine whilst I carry out the cycle.
Fast forward to day 20, I do another 40% water change, just to lower nitrates and "freshen" up the water if you like.
Fast forward to now, day 21 - I water test the pH and it has ROCKETED to over 8.0 - which has really unnerved me, if anything I thought the pH would have gone down, since I was taking away some of the soda bicarbonate I dosed on day 10. So i'm stuck now, trumped, no idea where to take it from here.

Any tips or advice? my instant tap pH is 7.2, and the water in my area is soft-very soft according to the water board.

TIA
James.
 
What it seems like to me is your tap may have some water hardener in it and once the chlorine gets out of there after dechlorination your water reverts to its original form of being soft.I would say dechlor some and leave it in a bucket then test it each day to see what level it gets to.
 
The pH is one part of water chemistry and it is closely tied to GH and KH. So first off, you need to ascertain the GH and KH. You should be able to do this from the data on the website of your municipal water authority if you are on city water. We just need to know the numbers of the source water.

Second, pH can vary according to the dissolved CO2 in the tap water. Testing pH of tap water should involve out-gassing the CO2, either by letting a glass of tap water sit 24 hours, or very briskly agitating it in a closed jar or something.

Third, if the GH and KH turn out to be low, this means the pH will naturally lower in an aquarium due to the build up of organics which produces CO2. That is not a problem in itself; fluctuating or changing pH is a real problem for fish. So you want to get this sorted out before any fish appear.

Dechlorinator should have no effect on pH, so I wouldn't worry about that. But you/we do need to know the values of the source water in order to sort this out.

Byron.
 
I see you give your location as GB. If you are in the UK it is unlikely that your water company's website will give your KH, only your total hardness. To find your KH, you will need to either buy a KH tester, or have a sample of tap water tested at a shop - ask them for the number and unit, not some vague words.
 
Hi all,

Thank you for your responses.
I do have the KH & GH test kits and will post the results tonight.

I do need to monitor the values of my tap water over time, however I don’t have an air stone or power head to agitate the water overnight.
If I leave the water standing for 24 hours without agitation will I still be able to get accurate pH results?

I’m hoping to get this sorted before I add fish - in the long term I want to achieve a steady pH of around 6.5

Kind regards

James.




Sent from my iPhone using Tapatalk
 
I do need to monitor the values of my tap water over time, however I don’t have an air stone or power head to agitate the water overnight.
If I leave the water standing for 24 hours without agitation will I still be able to get accurate pH results?

Yes. Sorry if I wasn't clear previously...you can use either method. Letting a glass of tap water sit 24 hours will out-gas the CO2. Agitating the water rapidly will also out-gas CO2. Some say the "let stand" method is more reliable.

Agitation can be as simple as putting some tap water in a small jar with a tight fitting lid and shaking it very briskly for a few minutes.
 
Thanks for the extra input Byron - I'll set some water out tonight and test it at the same time tomorrow.

my tank pH has now dropped to 6.6 - another big shift but now in the opposite direction.

I've just tested my instant tapwater for GH & KH (using API)
the KH test was finished after the first drop (1DKH) - it didn't even turn blue and went straight to yellow
the GH test took 4 drops to complete giving me a result of 4DKH

Look forward to hearing your thoughts/advice

James.
 
PS I have acquired some crushed coral in an attempt to raise hardness - put I don't want it to raise pH too much
I may start by adding a small handful in a mesh bag and run through the filter, and see how I go from there

let me know your thoughts
thanks

James.
 
PS I have acquired some crushed coral in an attempt to raise hardness - put I don't want it to raise pH too much
I may start by adding a small handful in a mesh bag and run through the filter, and see how I go from there
let me know your thoughts
thanks

I'll begin with this last question. You have been cycling this tank, so that is a different issue than a tank with fish. I have never "cycled" a tank artificially (I use live plants) so I am not well up with the effect of pH and other factors on cycling. So my comments are primarily going forward. If this were me, I would not mess around with the pH even now.

Crushed coral is not much of an effective buffer because it is only calcium. Aragonite or dolomite, which are both calcium and magnesium, are better. I have used both in a small mesh bag in the filter to raise pH a tad. During cycling this won't hurt. A little goes a long way; I put three tablespoons in the filter of my 90g and the pH overnight rose from around 6 to 7.6; I was lucky the fish managed through this, as that is a significant increase even over 24 hours. I currently only have this in my 33g with my Black Ruby Barbs, and 2 teaspoons maintains the pH around 6.6 (it would be at 5 or lower without this). But my other tanks I leave alone; I'll come back to this below.

I've just tested my instant tapwater for GH & KH (using API)
the KH test was finished after the first drop (1DKH) - it didn't even turn blue and went straight to yellow
the GH test took 4 drops to complete giving me a result of 4DKH

Look forward to hearing your thoughts/advice

This is what you/we need. Looking beyond the cycling now, to the intended fish...provided you go with soft water species, you will have no trouble and no need to mess with GH/KH/pH. It is always easier and safer to be able to use the source water directly (with a dechlorinator of course). It makes water changes simple, and in the event of an emergency when a major 80% WC might be needed this is no problem at all.

my tank pH has now dropped to 6.6 - another big shift but now in the opposite direction.

This is exactly what I would expect, given the GH and KH. The bicarbonate of soda has worn off, which is one reason this is not a good method, and should never be used once fish are present. The dolomite/aragonite is better, if needed. I wouldn't bother, depending upon the intended fish.

Back in post #3 I referenced organics. When fish are present, these will build. As they are broken down, they release ammonia and CO2. The ammonia is dealt with by plants and bacteria, no issue there (in a not overstocked tank). The CO2 produces carbonic acid, which in turn lowers the pH. The only thing to act against this natural process would be buffering, which is where the KH comes into play; the higher the KH, the stronger the buffering capacity. Here you have (like I do) a near-zero KH, so there is nothing to "buffer" and the pH will lower. I leave this alone, and it is interesting how it settles out differently in different tanks. In some the pH is well below 5, in others it is around 6, in one or two it is mid 6 range (the 33g only I buffer as I said above). Provided you have fish expecting this, there will be no problem. I can offer more when I know the intended fish.
 
Hi Byron - once again thank you for your response - and in-depth one at that

Firstly, ref the cycle - the only reason I raised the pH was to prevent the nitrogen cycle from stalling or failing. I found from my research a low pH (6.0 or below) can prevent the beneficial bacteria from colonizing.
But, fortunately I have done something right as it's almost complete now, which is a good result after only 22 days. It takes some people 3 months to achieve. So, I too will comment going forward and forget the cycle for now.

Secondly, intended species. - yes, all will be soft water species from the Amazon basin & all will be relatively easy fish to keep, Corydoras, maybe an L-Number, Apistogramma, and a dither fish of some sort from those areas. Tank will also be moderately planted (low tech)

Thirdly - It sounds like I'm overthinking, definitely. my pH level isn't a worry, as long as I can achieve something steady between 6-7 I'll be happy - I just don't want my hardness (or lack of it) to cause mad swings and effect the health of the fish, which of course is my up most priority. I expect my pH to drop even more as the Bicarbonate Soda wears off further.

I will be adding a large piece of bogwood to the tank once it's waterlogged - currently been soaking for a week.

would you recommend leaving things as they are for now?
And could you possibly recommend a pH testing kit that has a broader spectrum and can test below 6.0?

Thanks,

James.
 
As you intend live plants, you can basically forget about the cycle now. Plants need nitrogen, and aquatic species primarily prefer ammonium (ammonia). Fast growing species in particular, such as floating plants, are "ammonia sinks." They can assimilate a lot of it, more than the fish could ever produce (using your species/numbers, again overloading can wreck all this).

Nitrite will be a non-issue. In acidic water, ammonia changes into ammonium which is basically harmless. Plants will take it up, as will the Nitrosomonas bacteria that do establish. But studies have shown that plants are generally faster than the bacteria at assimilating ammonia/ammonium. The little that gets to the bacteria will continue the cycle, but you will never see ammonia or nitrite above zero from start to finish with live plants.

I would do some water changes to get rid of the bicarbonate, then plant and aquascape. If the bogwood will sink, I would add it now; any tanins will be beneficial, and you can always do a water change if the water tint is too much for you. When done, and the plants are showing signs of growth, add fish slowly. I'll leave which first for now, but some are better than others not because of any cycling issues but pure biology.

The pH may well drop below 6. Each tank is biologically unique. I only use the API test (down to 6), I did have a Tetra that went to 5, not sure if they still make this. A pH meter might register more of a range. I don't worry; I do weekly water changes of 60% or more, and the pH as I previously said has established and remains steady depending upon the individual tank. I just make sure the fish are suited. I'll add a couple photos of some of my Amazon tanks. Lots and lots of wood, dried leaves, sand...these are the prime ingredients. The plants tend to multiply rapidly, beyond what I might initially intend, but that's fine; you can always pull them out at some point.
 

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Hi Byron,

I added the wood a couple of days ago, looks pretty good.

So, in a well planted tank the waste produced by the fish is absorbed by the plants and not so much by the bacteria colony within the filter?
Would this still work with a moderate stock level of fish? I won’t be having anything big but I’m thinking numbers.
Let’s say an example stocking of;
10 x Sterbai Cory
20 x Rummy Nose
2/3 x Apistogramma Macmasteri

And secondly will the plants need to get established and healthy before they start to use the ammonia or are they ready to “feed” on it?

As expected my pH has dropped below 6.0 - I have tested the water and this has stopped my ammonia dosing from being converted into Nitrite - effectively stalling my cycle.
I don’t know which way to play it now - boost the pH back up so the bacteria will resume their processes or leave the pH and just add plants when I can

Thanks
James



Sent from my iPhone using Tapatalk
 
So, in a well planted tank the waste produced by the fish is absorbed by the plants and not so much by the bacteria colony within the filter?
Would this still work with a moderate stock level of fish? I won’t be having anything big but I’m thinking numbers.
Let’s say an example stocking of;
10 x Sterbai Cory
20 x Rummy Nose
2/3 x Apistogramma Macmasteri

We need to clarify "waste." We have the solid waste, fish excrement, which sinks to the substrate and works down into it, aided by snails, and is then broken down by bacteria. The nitrifying bacteria involved in cycling is not directly relevant to this, but primarily to the ammonia directly released into the water by fish respiration. Ammonia is also being released as organics like the "waste" decompose of course.

Plants will take up the ammonia/ammonium quite rapidly (fast growers anyway). They also use other nutrients resulting from the solid waste in the substrate, such as CO2. But any minerals in the fish foods will eventually get to the plants.

The amount of ammonia that plants can assimilate is substantial. You are no where near an issue with these fish.

And secondly will the plants need to get established and healthy before they start to use the ammonia or are they ready to “feed” on it?

I would want to be sure the plants are growing. Newly-acquired plants can take a few days to settle. When I re-set my tanks (which is a total tear-down comparable to a new tank) I am obviously using my growing plants, so I don't need to worry. And there will be bacteria on the plants and wood I re-use. But as you're starting afresh, get the plants growing, fast-growing species, first.

I would not worry about the pH for these fish, so let it go. Water changes to remove artificial ammonia, add plants, off you go.
 

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