Cycling, lots of pH crashes, will that happen too when I get fish?

[amaranth13]

So, I'm cycling a 10 gallon tank. I have enough ammonia eating bacteria for them to remove 4 ppm of Ammonia over 24 hours. The nitrite eating bacteria are eating all of that nitrite except for 0.25 ppm, so I'm almost done My water is 6.8 pH and 2 Kh and 2 Gh. The problem is I'm not getting any further because I'm getting pH crash after pH crash, for example in one day the pH goes from 6.8 to 6.0 and I've had that happen several times, and over two days as well. It's been very stressful having to do a complete water change almost every day, even though it's only a 10 gallon tank. Also because I'm having trouble reading the API test kit pH chart for everything between 6.t and 7.2 (my vision is not great), and this is clearly my biggest issue for fish, I bought a pH meter, and calibrated it.

I went to my LFS (who are very well known and they grow live corals, they must know what they're doing) and asked what to do. I left the store with a pH buffer to pH 7 called 'neutral regulator' from Seachem. I put the stuff in the water with a complete water change (90 % I can't quite get that last 10 percent out), and the pH is an even 6.8, no more crashes so now it can catch up. But I was testing the water just after I mixed it and it looked very high in my test tube. So when I got the pH meter today and I tested a mix of the neutral regulator (the correct amount) and my tap water the pH is 7.6! It didn't go down over an hour. It comes down over a night. This is fine to grow beneficial bacteria, but it's not fine (i think) when having to do water changes with fish in. With only a 10 gallon I think I'll need to do at least a 50 percent every week if not more, and that means shocking the fish.

I live in a small place, and the 10 gallon and a 5.5 gallon betta tank is all I'll have room for. There is no room to put out several buckets overnight for water changes to let the neutral regulator balance itself out overnight. I have also tried some aragonite in the filter, that is with the betta tank right now which is cycling great, no pH crashes, due to the Aragonite and the pH only rose to 7.2, but I want ember tetras in the 10 gallon and that pH is high for them. And using Aragonite would have the same water changing pH difference problem. I also tried a pinch of baking soda in a bucket of dechlorinated tap water and that raised the pH to 8.2 and the Kh remained 2.

I can handle doing two 75% water changes a week, but a higher percentage and the fish won't have a place to go to, it will already be bad for them in 2.5 gallons, even if for 10 minutes. I checked how many 2.5 gallon buckets I need to refill it completely and it's four, so there would be 2.5 gallons left for the fish. But I don't think I can manage to do them every night. I know I got the advise not to mess with the pH but at this point I'm worrying that my tap water with decholorinator is not buffered enough to keep the fish safe for 4 days. Or is that very different while doing cycling than while having fish? Apart from having the tap water with dechlorinator only in the tank without buffering, so I can replace with tap water without problems, are there other options for adding Kh or another type buffer to the tap water without it making too big a difference with the water changes?

Any ideas would be greatly appreciated.

 

[Colin_T]

The pH is dropping because there is no KH (carbonate hardness) in the water. The carbonates and bicarbonates neutralise acids in the water and stop the pH dropping.

Get some limestone, shells or dead coral skeleton/ rubble and put some in the tank or filter. These are made from calcium carbonate and will stop the pH dropping. You add a piece and monitor the pH over a week or two, if it continues to drop you add some more and monitor the pH. Continue adding limestone, shells or coral rubble until the pH stabilises.

 

[seangee]

What is your tap water pH 24 hours after it comes out of the tap? What is the pH in your tank if you don't add the buffer.
Your water supply is acidic. Your water company probably adds temporary alkalinity to the water because acidic water corrodes the pipework - so the drop in the first 24 hours is expected and normal.
I would let the tank do its own thing and wait to see where it stabilises. With you GH/KH you are going to want to keep soft water fish and these are mosty fine with acidic water. I have 2 tanks with a pH of around 6 and never have any problems

 

[amaranth13]

Colin_T: I'm using aragonite in the betta tank filter whiile cycling, I get a Kh of 4 and a Gh of 6 and a pH of 7.2. I can't get crushed coral where I am or affordable online, and saw in several sources online that aragonite was good too. But I can try shells, I can find those, and I can look around for limestone if those are better than aragonite. The ember tetra can deal with 7.2, though it's on the high end for them, I am just worried about adding 6.8 pH water during a water change to a 7.2 pH tank.

Seangee: The pH after 24 hours (which I should have mentioned, I tested it) is also 6.8. I am planning on Ember Tetras which would do well with acidic water. When I put it inn the tank after an hour or so it's 6.8 in the tank but it goes down fast, because of the bacteria. Seangee you have no problems if you add higher pH tap water to your pH 6 tank? I'm worried about it because even a 25% water change would still cause a quite different pH in the tank? Or am I just seeing problems where there are none? I would -love- not to have to use any chemicals or things in the filter.

Thank you both for your advise!

 

[seangee]

TBH I don't even check. My tanks are 6.0, 6.5 and 7.2. The 7.2 tank has added minerals because the fish in there don't like water that is too soft. In theory the other 2 tanks should be identical. I haven't done anything else to change anything in any of the tanks. Each tank is a unique environment and I just let them find their own pH.

All 3 tanks get exactly the same water and a 75% change every week. The water in my storage totes is 7.0. Remember pH does fluctuate during the day, both in nature and in tanks.

I only even know the values because someone gave me a digital pH tester yesterday and I was curious. Before that I assumed 2 of the tanks were identical because both read the lowest value possible on my usual tests

As long as it doesn't keep dropping I wouldn't worry about it.

 

[Colin_T]

Aragonite is fine to use instead of shells, limestone or coral rubble.

You can fill a bucket with tap water and spread a layer of aragonite over the bottom of the bucket and it will raise the pH over a day or two. When the pH is 7.2, use it for a water change.

A pH of 7.2 is fine for all tetras unless they are wild caught.

 

[amaranth13]

Thank you both!! I also was a little over-detailed and looked up the formula for mixing different pHs at either 50% and 75% water changes with the buffer or with aragonite. Sorry if this is hard to follow, I am a math enthusiast as well as now an aquarium enthusiast. The formula is M1V1+M2V2=MV. V is volume, M is worked out in the calculations. I hope there is someone here who can tell me if I did it right!

M1V1+M2V2 =MV
pH=6.8 M1=10^-6.8 V1=1 water from tap with only dechlorinator
pH=7.2 M2=10^-7.2 V2=1 original water with aragonite
(10^-6.8*1 + 10^ -7.2*1)/2=(0.000000158+0.000000063)/2=0.000000111
pH=-log[0.000000111]=6.95
So using Aragonite would create a 7.2 pH with a good buffer, and a 50 percent water change would be fine, a drop of 0.2 pH, which should be safe

M1V1+M2V2 =MV
pH=6.8 M1=10^-6.8 V1=1 original water with buffer
pH=7.6 M2=10^-7.6 V2=1 tap water with buffer
(10^-6.8 *1+ 10^ -7.6*1)/2=(0.000000158+0.000000025)/2=0.000000091
pH=-log[0.000000091]=7.04
The original water would be buffered after resting a full night. The result if I mix equal 6.8 and 7.6 amounts of water I would get pH of 7.
This means I could do a 50 percent water change right after mixing it with the buffer with a raise of 0.24 pH, which should be somewhat safe

M1V1+M2V2 =MV
pH=6.8 M1=10^-6.8 V1=3 water from tap with dechlorinator
pH=7.2 M2=10^-7.2 V2=1 original water
(10^-6.8 *3+ 10^ -7.2*1)/4=(0.000000475+0.000000063)=0.000000135
pH=-log[0.000000135]=6.869
A 75% percent water change with the aragonite would cause a drop of 0.3 pH, not safe

M1V1+M2V2 =MV
pH=6.8 M1=10^-6.8 V1=1 original water with buffer
pH=7.6 M1=10^-7.6 V1=3 water from tap with buffer
(10^-6.8*1+10^-7.6*3)/4=(0.000000158+0.000000075)/4=0.000000058
-log(0.000000058)=7.236
This 0.75% water change with buffered water would cause a 0.4 pH raise, not safe

Conclusion: The buffer is somewhat high pH difference if not left to stand overnight for the 50% and unsafe for the 75% water change. The aragonite is safe if dechlorinated tap water is added to aragonite water, but only in a 50% water change, not a 75 percent. If I don't get pH crashes after I'm cycled the best solution is of course no aragonite or buffer at all.

So, I'm going to take both your advise, I'm going to remove all the buffered water with a 90% water change after I'm done cycling (can't manage 100 percent), not add any buffer or aragonite, keep a close eye on the pH for a week several times a day (I work but my husband is at home so he can help) and if it doesn't crash I think I'll be ok and measure it once a day for a few weeks longer, then go to less often. If it does show signs of crashing I'll add the aragonite in very small increments because I'll have fish in. It's more natural than the buffer. I want to do two times a day pH testing the first week because if the crash happens like I've been seeing of 0.8 in a day I will surely end up with dead fish.

Does this plan sound sensible or am I overdoing things? I guess it's normal for new aquarium people to get a little overinvolved

 

[Byron]

This is the wrong approach, what is being primarily suggested in this thread. The OP lives in western Oregon which has water near-identical to mine up in Vancouver, BC. Near-zero GH and KH. The water is naturally very acidic, and in Vancouver they add soda ash to raise the pH (only) but this is temporary.

Do not use buffers, aragonite, or similar. Depending upon the intended fish, this is totally unnecessary and only going to cause problems for you and the fish. My Ember Tetras are healthy and spawning with some fry even surviving and they are in water that has a pH well below 5, so low I cannot even measure it. This compares to their habitat environment.

My fish have thriving under these conditions for 30 years. So long as you select soft water species, you're fine. Several years ago I did buffer one tank with dolomite, keeping the pH at 6.4 to 6.6 but that was for specific fish.

 

[amaranth13]

Yeah i've chosen soft water Ember tetras because of my water. I am just worried about my pH going that low in a day. I guess since you have no issues, Byron, I should definitely try without any buffers or aragonite first.

 

[Byron]

Yeah i've chosen soft water Ember tetras because of my water. I am just worried about my pH going that low in a day. I guess since you have no issues, Byron, I should definitely try without any buffers or aragonite first.

There is a reason for the pH lowering from 6.8 to 6 in a day, and successive days. First, the near-zero GH and KH provide no buffering, so the pH will do what it naturally does in any aquarium with organics (as from fish), lower. As the organics are broken down, CO2 is produced; CO2 produces carbonic acid in the water, and thus the pH lowers. This is natural and normal in all aquaria. What often prevents the pH doing this is the degree of "buffering" the GH/KH provide.

The pH of your tap water presumably is 6.8 if I'm reading correctly. I would suggest the water authority is likely adding something to raise it to this level, because naturally I suspect it is much lower. In Vancouver they began adding soda ash in 2001, to raise the pH to 7.0 to 7.2; without this, prior to 2001, the tap water pH was in the low 6's and even 5's. This corrodes pipes so many places that have this soft acidic water will add something to raise the pH. This is often temporary. The pH in the aquaria will be 7.0 if I set up a new tank, as I recently did when I moved and tore down all my existing tanks. The pH of 7.0 to 7.2 lowered down to 6 by morning, with no fish in the tank but with plants, snails, and bacteria. It stabilized in each aquarium when fish were added and it never varies. Water changes of 60-70% performed weekly with the 7.0 pH tap water do not raise the pH in the tanks more than a couple decimal places.

Monitor the pH but do not do anything to affect it (adding buffers, calcareous whatever, or more than necessary water changes). See where it ends up, and I can all but guarantee it will stay there if you leave it alone.

 

[amaranth13]

If they add something to my municipal water to make the pH go up would that show a lower pH after 24 hours? I did measure after 24 hours in a bucket still getting 6.8, but I didn't aerate it (didn't have an airstone yet, now I do, so I can test it again with aeration). I will not use any buffer or aragonite or anything else to mess with the pH unless I see pH crashes happen, it seems that it's a lot less likely to happen with fish than during cycling. Thanks for sharing your experience!

 

[Byron]

If they add something to my municipal water to make the pH go up would that show a lower pH after 24 hours? I did measure after 24 hours in a bucket still getting 6.8, but I didn't aerate it (didn't have an airstone yet, now I do, so I can test it again with aeration).

It depends upon what they add, if anything. In my situation the pH is 7.0 or 7.2 out of the tap, and remains the same when I out-gas any CO2, but I don't think I have ever let a glass sit 24 hours so I'm not sure. But in the aquarium, the pH rises by perhaps a decimal point or two, and after two hours is back where it normally is and has been for months. So I can say that the soda ash added here temporarily increases the pH but there is no buffering capacity to this so it falls in accordance with the natural buffering in the aquarium. Do the second test and post results.

So far what you have described is not technically a pH crash but normal chemistry processes. I think once attempts to alter the pH are missing, the pH will behave "normally" for the chemistry in your aquarium. And "normally" seems in this case to be lowering naturally, which as I said previously is not really a problem unless you attempt by some means to interfere with it, then you have fluctuating pH which is a problem.

 

[amaranth13]

Yeah that makes sense. I was just worried if the pH reacts like that to cycling and adding 4 ppm a day for the bacteria to process and it has this result of going from 6.8 to 6.0 in one day, that that might happen when there are fish in it. And what would happen if you let it stay at 6 (not during cycling, obviously, it stops the beneficial bacteria from growing, but with the fish) how they will react to water changes with higher pH water. But clearly I'm worrying too much, since your fish have no problems with you doing water changes, and it sounds like your pH 5 tank has a much larger difference between a pH well below 5 and your tap water of about 7, as me with 6.8 to 6. I had no idea fish could handle such large differences!

 

[Byron]

Yeah that makes sense. I was just worried if the pH reacts like that to cycling and adding 4 ppm a day for the bacteria to process and it has this result of going from 6.8 to 6.0 in one day, that that might happen when there are fish in it. And what would happen if you let it stay at 6 (not during cycling, obviously, it stops the beneficial bacteria from growing, but with the fish) how they will react to water changes with higher pH water. But clearly I'm worrying too much, since your fish have no problems with you doing water changes, and it sounds like your pH 5 tank has a much larger difference between a pH well below 5 and your tap water of about 7, as me with 6.8 to 6. I had no idea fish could handle such large differences!

The thing that has to be kept in mind is that once you have fish in an aquarium (cycled obviously) and it begins to become established, it will have its inherent stability. If you leave it alone, meaning not go adding chemicals, buffers, etc, the stable biological system will resist any variation like water changes. Each tank is different. I have tanks ranging from below 5 up to mid-6 and my once-regular weekly (prior to the water change) pH tests over several months, then periodically for a couple years, showed the pH never varied in all that time by more than a decimal place. That is stability. Provided the fish species are suited to this, nothing could be better or safer.

 

[amaranth13]

Thank you, Byron. I will need to remember that an aquarium with ammonia given by fish is very different from drops from a bottle. Can I ask a question about cycling if you have an idea? I've been having no problem at all converting 3 ppm of ammonia to nitrites to about 0.1 ppm of ammonia left, which is what my water comes with. Then the other bacteria change that nitrite into nitrate, except for the last 0.25 ppm. I've been stuck on this amount for a week now, but I get the pH going to under 6.5 all the time (sometimes as low as 6.0 when all nitrification stops) and sometimes it's one day and sometimes it takes two. I wonder if I'm having trouble growing the nitrite to nitrate bacteria to a sufficient level because of the lower pH?

Is this likely, and if so, do you have any tips? My water does not come with any nitrites at all from the tap. So when I get home from work I check the pH and get my values, which the last week every day have been 0 ppm Ammonia, 0.25 ppm nitrite, and more nitrates than I'd expect, 20-40,. (If I did a water change yesterday it's about 20, and 2 days ago 40, which seems to be too high. I thought my test was bad but I got a new one and it shows the same values.. ) If the pH is under 6.5 I do a full water change (I got a pH meter cause I have trouble reading the API test. And I calibrate it before testing every day in the buffer solution because it can't seem to hold it's calibration for 24 hours, unlike the 48 hours it says.) After that I dose again with 3 ppm ammonia. rinse, repeat.

Is it the full water change? (or more 90 percent). But I'm trying to keep my pH at about 6.8 as it comes from the tap (and after 24 hours). I am also cycling a 5.5 gallon betta tank along with the 10 gallon, and strangely enough that one has the same problems with having 0.25 ppm nitrites left after 24 hours, even though the ammonia is gone, and I up that to only 2 ppm, because it will only have a betta. I get a bit less low pH problems in that one. I use prime water conditioner, the same ratio, and apart from 2 or 3 ppm I'm not doing anything different..

so any thoughts would be appreciated, I'm sorry I'm asking so many questions.