Ph Keeps dipping drastically during cycle

Currently cycling a 55g, getting close to being finished I think but it's in the nitrite stage. Anyway my ph keeps going really low, I've been doing 50% water changes every day to get it back up because it keeps dipping to 6-6.6, which from my understanding will stall the cycle. Should I continue doing this to keep the ph up or will it cause any issues? I don't really mind having to do it as having a python makes it really easy and I'm thinking it should be finished within a week or so. But the ph gets up to about ~7.5 after water change and within about 10 hours after testing it's down to 6.6, is this going to affect my cycle if it's not constantly above 7? And what ph exactly affects the cycle? I've heard anything below 6, 6.5, and 7 and I'm not sure which is accurate. Anyway is it normal for ph to drop this much during cycling, and does it mean it's almost finished? Thanks for any help!

 

• Does this tank have the enhanced substrate that's designed for optimum plant growth? I understand some of them can alter pH.
• Do you have any kind of decoration that might lower it (rocks, driftwood, etc)?
• Do you know your kH? There are other people here who are much more knowledgeable about this subject than I am, but I understand that the lower it is the more unstable pH can be.

 

• Does this tank have the enhanced substrate that's designed for optimum plant growth? I understand some of them can alter pH.
• Do you have any kind of decoration that might lower it (rocks, driftwood, etc)?
• Do you know your kH? There are other people here who are much more knowledgeable about this subject than I am, but I understand that the lower it is the more unstable pH can be.

I just have the aquarium sand sold by petco, nothing that to my knowledge affects ph. I only have an artificial rock as decor, so again nothing that would affect ph at all. I do not know my kH. From the amount of reading I've done it seems like it isn't abnormal for ph to drop when cycling, I just didn't think to this extent would be common.

 

Welcome to Fishlore

It may not be the cycling process causing the pH to drop so drastically. You can test this out by putting some of your tap water straight from the tap in a container. Run the pH test on this water right away and then again in 24 hours. If at all possible run an airstone or just an airline in this container. Water movement in the container will mimic what's happening in your tank.

If the pH drops in this container it will tell us your tap water doesn't contain the buffers needed to hold the pH level up. You can counteract this in the tank by adding crushed coral to your filter. It will very slowly dissolve and as it does it will stabilize your pH up close to the level straight out of the tap.

 

Welcome to Fishlore

It may not be the cycling process causing the pH to drop so drastically. You can test this out by putting some of your tap water straight from the tap in a container. Run the pH test on this water right away and then again in 24 hours. If at all possible run an airstone or just an airline in this container. Water movement in the container will mimic what's happening in your tank.

If the pH drops in this container it will tell us your tap water doesn't contain the buffers needed to hold the pH level up. You can counteract this in the tank by adding crushed coral to your filter. It will very slowly dissolve and as it does it will stabilize your pH up close to the level straight out of the tap.

I actually have another smaller tank cycling as well, though it started cycling after this one so it's further behind. I tested the ph in this one yesterday and it's still around 7.6 so I don't think it's the tap water.

 

I actually have another smaller tank cycling as well, though it started cycling after this one so it's further behind. I tested the ph in this one yesterday and it's still around 7.6 so I don't think it's the tap water.

In that case the crushed coral should help stabilize the pH in this tank. Normally the pH doesn't drop this drastically and so quickly. I will still recommend you run the 24 hour test. It isn't a big problem right now since there are no fish in this tank (I am assuming this is a fishless cycle) but if it continues to happen once fish are added it could cause problems.

 

In that case the crushed coral should help stabilize the pH in this tank. Normally the pH doesn't drop this drastically and so quickly. I will still recommend you run the 24 hour test. It isn't a big problem right now since there are no fish in this tank (I am assuming this is a fishless cycle) but if it continues to happen once fish are added it could cause problems.

Yes it is a fishless cycle so it's not a massive deal, my primary concern is that the low ph will affect the cycle. From what I understand having a low ph can slow down or even bring a cycle to a halt which I obviously want to avoid; I plan on picking up the crushed coral tonight when I am off of work and putting a bag of it in my filter. My question now is if having the ph that low for a few days now off and on may have impacted my cycle? Has it potentially hurt it, or could potentially hurt it if the ph is that low consistently?

 

Yes it is a fishless cycle so it's not a massive deal, my primary concern is that the low ph will affect the cycle. From what I understand having a low ph can slow down or even bring a cycle to a halt which I obviously want to avoid; I plan on picking up the crushed coral tonight when I am off of work and putting a bag of it in my filter. My question now is if having the ph that low for a few days now off and on may have impacted my cycle? Has it potentially hurt it, or could potentially hurt it if the ph is that low consistently?

When the pH gets too low it can slow the cycling process down. I always recommend trying to keep it up to at least 7. At 6.5 it slows down. At 6 it can almost stop. It isn't going to kill your bacteria but it could start going dormant thus slowing the cycle down. The CC should keep it from dropping so low.

 

I was able to test my kh and it reads very low, I believe at 0. However when I test my tap water it reads moderate (80). Does cycling affect kh? My other aquarium that is cycling has a low kh as well, though it's not quite at 0 like this one is. Also I'm not sure if hardness matters at all, but I'm getting consistent readings that my gh is very hard (300). Anyway I'm wanting to know if this is an issue I'll only be dealing with during the cycle or if this will continue into getting fish introduced, it will be an mbuna tank so ph will be a major factor. I can continue doing water changes every day to keep the ph up somewhat while it cycles.

 

I was able to test my kh and it reads very low, I believe at 0. However when I test my tap water it reads moderate (80). Does cycling affect kh? My other aquarium that is cycling has a low kh as well, though it's not quite at 0 like this one is. Also I'm not sure if hardness matters at all, but I'm getting consistent readings that my gh is very hard (300). Anyway I'm wanting to know if this is an issue I'll only be dealing with during the cycle or if this will continue into getting fish introduced, it will be an mbuna tank so ph will be a major factor. I can continue doing water changes every day to keep the ph up somewhat while it cycles.

The cycling process alone should not be so drastically changing your numbers. Something else is going on. I am going to call in RayClem and MacZ to see if they have any thoughts about what is happening. We don't want to see this happening once fish are in the tank so need to get to the bottom of it before then. Hopefully they will be able to help.

 

The cycling process alone should not be so drastically changing your numbers. Something else is going on. I am going to call in RayClem and MacZ to see if they have any thoughts about what is happening. We don't want to see this happening once fish are in the tank so need to get to the bottom of it before then. Hopefully they will be able to help.

I'm not certain then, cause I don't have anything in my tank that should be affecting ph at all. Any help would be appreciated!

 

Allright, mattgirl why did you call me? Problem solved.

I was able to test my kh and it reads very low, I believe at 0. However when I test my tap water it reads moderate (80). Does cycling affect kh? My other aquarium that is cycling has a low kh as well, though it's not quite at 0 like this one is. Also I'm not sure if hardness matters at all, but I'm getting consistent readings that my gh is very hard (300). Anyway I'm wanting to know if this is an issue I'll only be dealing with during the cycle or if this will continue into getting fish introduced, it will be an mbuna tank so ph will be a major factor. I can continue doing water changes every day to keep the ph up somewhat while it cycles.

KH reads almost zero in the tank and only 80 in the tap? This tank is not going to hold Mbuna unless you put a good load of crushed coral in the filter and use limestone for hardscape. And I'm not talking about a few kilos, I'm talking a whole reef (as would be necessary for Mbuna).

This issue will continue, unless cc and limestone are used, as beneficial bacteria use up carbonates and Nitrates switch to an acid form when solved in water.

 

Allright, mattgirl why did you call me? Problem solved.



KH reads almost zero in the tank and only 80 in the tap? This tank is not going to hold Mbuna unless you put a good load of crushed coral in the filter and use limestone for hardscape. And I'm not talking about a few kilos, I'm talking a whole reef (as would be necessary for Mbuna).

This issue will continue, unless cc and limestone are used, as beneficial bacteria use up carbonates and Nitrates switch to an acid form when solved in water.

Thank you for stopping in and helping to confirm what I was thinking. I didn't think the cycling process alone was causing what we were seeing. The almost total lack of KH is behind the problem with the pH and if not addressed now it will be a problem once fish are added.

Thank you for mentioning the limestone too. I had forgotten about that.

ae277 Getting and keeping the pH up with both crushed coral and limestone should help stabilize this water. Your cycle should continue to move forward and once done should be a safe home for your future water pets.

 

MacZ beat me to it. Thanks Mac.

As usual, his advice is right on target. Lake Malawi Cichlids like water that is high in general hardness, high in carbonate hardness, and a pH of 7.8 or higher.

As MacZ recommends, adding crushed coral will stabilize things.

Crushed coral is aragonite which is composed primarily of calcium and magnesium carbonates along with some trace minerals. As the aragonite dissolves, it will raise the calcium and magnesium concentrations which will stabilize the general hardness. The carbonates will neutralize any acids in the water raising both carbonate hardness and pH. The lower the pH in the tank, the faster the aragonite will dissolve. As the GH and KH increase, the rate of dissolving will lessen. Thus, the process is self limiting and will produce conditions ideal for a mbuna tank. You could even use crushed coral as the substrate in the tank.

In tanks where the desired levels of hardness and pH are lower than that required for mbuna, you have to be careful not to add too much crushed coral. In that situation, it is best to place the crushed coral in a fine mesh bag and put the bag in the filter. That way, it can easily be removed when the desired carbonate hardness and pH levels have been reached.

 

If you are doing a fishless cycle I would ignore PH until it is done and just keep the other levels from going off the charts with water changes. Substrate and filter sponge don't mind PH swings.

I imagine the PH is swings wildly because Ammonia is a strong base and it is being converted to other things.

 

If you are doing a fishless cycle I would ignore PH until it is done and just keep the other levels from going off the charts with water changes. Substrate and filter sponge don't mind PH swings.

I imagine the PH is swings wildly because Ammonia is a strong base and it is being converted to other things.

Unfortunately, you cannot ignore the pH. Beneficial bacteria are sensitive to pH. If the pH goes too low, the bacteria will no longer multiply as desired and the cycle will stall out. It is best to keep the pH at neutral or slightly above. You want the cycle to be carried out under similar conditions (GH, KH, pH) that are expected once the fish are added so appropriate colonies of bacteria will develop. You do not want to cycle a tank at acid pH levels and then increase pH to 8.0 for addition of African cichlids.

 

You want the cycle to be carried out under similar conditions (GH, KH, pH) that are expected once the fish are added so appropriate colonies of bacteria will develop. You do not want to cycle a tank at acid pH levels and then increase pH to 8.0 for addition of African cichlids.

They say, the higher you go with pH, the higher the percentage of nitrosomonas and nitrobacter (Though it seems those have quite little influence in aquarium filters.), the lower the higher the percentage of archeans and nitropira.
Freshwater Recirculating Aquaculture System Operations Drive Biofilter Bacterial Community Shifts around a Stable Nitrifying Consortium of Ammonia-Oxidizing Archaea and Comammox Nitrospira

 

They say, the higher you go with pH, the higher the percentage of nitrosomonas and nitrobacter (Though it seems those have quite little influence in aquarium filters.), the lower the higher the percentage of archeans and nitropira.
Freshwater Recirculating Aquaculture System Operations Drive Biofilter Bacterial Community Shifts around a Stable Nitrifying Consortium of Ammonia-Oxidizing Archaea and Comammox Nitrospira

Thanks MacZ. My knowledge of chemistry is far greater than my knowledge of microbiology, so I knew that pH affected the bacteria colonies, but not the specifics. Thanks for adding the details.

 

Unfortunately, you cannot ignore the pH. Beneficial bacteria are sensitive to pH. If the pH goes too low, the bacteria will no longer multiply as desired anyd the cycle will stall out.

There is no reason to expect stable PH when you are dumping in chemicals that change the PH to levels that would kill any livestock. Unless you plan on altering the PH the entire life of the aquarium why do it at the begining?

 

There is no reason to expect stable PH when you are dumping in chemicals that change the PH to levels that would kill any livestock. Unless you plan on altering the PH the entire life of the aquarium why do it at the begining?

Yes, ammonia is a alkali/base and will raise pH. Ammonium chloride is a weak acid. So one raises the pH, the other lowers it However, if you are only adding enough to achieve a 2 ppm concentration, the effect will not be that great unless you water is low in buffering capacity/carbonate hardness. If you are adding enough to change the pH drastically, you are adding too much. It takes only 76 mg (.076 g) of pure ammonia per 10 gallons of water to achieve that concentration. Clear ammonia is about 30% concentration. Thus, it takes about 250 mg (0.25 g or 0.25 ml) of clear ammonia per 10 gallons of water to achieve that concentration. At 20 drops per ml, 0.25 ml is only 5 drops of ammonia per 10 gallons. That is not very much at all and should not be sufficient to cause a big swing in the pH.

The problem in the case of the OP is that he intends to keep mbuna which require hard, alkaline water and he trying to cycle the tank under acidic conditions. Thus, if he waits until the tank is cycled before raising the pH level, he is going to mess up the bacteria colonies and have to recycle the tank to develop appropriate colonies of bacteria for that pH level. I am not saying that it will take as long to complete the cycle the second time around, but why do that at all. Sooner or later he will need to add crushed coral to stabilize the pH above 7.8, so it is better to do that now rather than later.