pH during cycling

chrisnolan

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Hi, is it normal for pH readings to fluctuate during cycling. My tap water is 6.4 and 2.24 Clarke so very soft. I am currently cycling and at day 23. Plants growing well and am up to dose 5 of ammonia. My test results have been pretty steady apart from last few days when my pH level has risen to 7.6 on day and then dropped back again. Just tested again today and now reading 6.0
 

Ichthys

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Yes if there’s hardly any KH. Bacteria use KH so will lower it, and as it gets near depleted the pH will drop. Add some bicarb to raise it to a safe level.
 

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Add some bicarb to raise it to a safe level.
That's bicarbonate of soda (also called baking soda) found in the home baking section in the supermarket. NOT baking powder!
The big water change when the cycle is finished will remove the bicarb.

Try 1 x 15 ml spoonful per 50 litres. Take some tank water out, dissolve the bicarb in that then pour back into the tank. Wait half an hour for it to mix in, then test the pH. If it's still very low, add some more.
 

Ichthys

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That's bicarbonate of soda (also called baking soda) found in the home baking section in the supermarket. NOT baking powder!
The big water change when the cycle is finished will remove the bicarb.

Try 1 x 15 ml spoonful per 50 litres. Take some tank water out, dissolve the bicarb in that then pour back into the tank. Wait half an hour for it to mix in, then test the pH. If it's still very low, add some more.

I would start with even less, it’s powerful stuff.
 

Essjay

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I need to point out that bicarb is only for when there are no fish in the tank. It should not be used once fish are in there, especially soft water fish. Since the OP has very soft water, the fish need to be soft water fish.
For reference, the two hardness units used in fish keeping are dH and ppm. 2.24 Clark = 1.8 dH and 32 ppm.
 
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chrisnolan

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thank you all it's really interesting and I am still learning about all this stuff. Test today shows the same reading of 6 so will get the bicarb tomorrow. Question though, since I am nearly at the end of the cycling, hopefully, and almost ready to get my first lot of fish, what will happen if it drops again after the fish are added. I am looking at soft water fish, tetras mainly and maybe a few shrimp later on. Was hoping to add a couple of nerite snails but I read that they prefer harder water than what I have so will have to reconsider those. Added my dose 6 of ammonia today too so nearly there I think
 

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Once fish are in the tank, weekly water changes will replenish the KH which is used up during the week. But you will still find that your pH drifts downwards. This is not a problem as long as you keep fish which need soft acidic water - so no guppies, for example. You will already have the bacteria you need so it's just a matter of keeping the population stable as some bacteria die, rather than significantly increasing their numbers as in cycling.

Shrimps and snails may well be a problem though. Shrimps need calcium (that's GH) to grow new exoskeletons when they shed the old one. Snail shells erode in acid water.
I know that there are calcium supplements which are intended for shrimps, these increase GH slightly. Members who use these will be able to help.
 
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chrisnolan

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Once fish are in the tank, weekly water changes will replenish the KH which is used up during the week. But you will still find that your pH drifts downwards. This is not a problem as long as you keep fish which need soft acidic water - so no guppies, for example. You will already have the bacteria you need so it's just a matter of keeping the population stable as some bacteria die, rather than significantly increasing their numbers as in cycling.

Shrimps and snails may well be a problem though. Shrimps need calcium (that's GH) to grow new exoskeletons when they shed the old one. Snail shells erode in acid water.
I know that there are calcium supplements which are intended for shrimps, these increase GH slightly. Members who use these will be able to help.
ahh, that makes sense, thank you for that. I will reconsider the shrimps and snails for this tank, was going to use them the help with algae but will look at suitable fish instead. Thanks for your help
 

Ichthys

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After the cycle, the fish will be producing far less ammonia, so water changes will probably be enough. If not you could add a very small bag of crushed coral, aka coral gravel (Not coral sand) to your filter. It dissolves KH into the water very slowly. The right amount would keep the KH as it is and prevent it dropping.
 
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added the bicarb yesterday as suggested, left overnight and retested this morning. My pH has now gone up to 7 which I am pleased about. I think the cycling is almost done, added dose 7 of ammonia this morning and fingers crossed should be ok tomorrow. One thing that has happened overnight is that I seem to have had a rapid growth of algae in the tank. The front glass is covered with little spots of brown/green algae and there is lots of hair type stuff on the back filter sponge and some of the plant leaves. Will this go with the water change at the end of they cycling period or should I try and do something about it now
 

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TwoTankAmin

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First- did you outgass your tap water before you tested it for pH? If not you need to retest after doing 1 of 2 things. Let a clean glass of water sit out over night beofre testing or else use and air pump to bubble the water in the glass for about 15 minutes and then test it. You are trying to outgas any excess CO2.

The fishless cycling article here is meant for tanks that contain no or almost no live plants. The more plants one starts out with, the less useful the guide becomes.

Here is why. Live plants use ammonium. They do this way faster than the bacteria can use NH3. So, the more plants one has in any given tank, the less bacteria there will be. However, there will never be no bacteria no matter how many plants one has.

Basically what you are doing is feeding the plants not establishing large bacterial colonies.

Sodium Bicarbonate -
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 https://fins.actwin.com/aquariafaq.html

I really need to write the next article re cycling which deals with planted tanks and seeding bacteria to jump start the cycle. Both of these things alter how one should approach insuring that a tank is not in danger of harming fish due to ammonia. When it comes to plants and cycling, there is no way to reduce things to a basic formula the way it can be done when no plants are involved. The reason is due to the great variety of potential plants one can have combined with different planting levels.

Basically. if your tank can clear 2 ppm of ammonia in 24 hous or less, you can pretty much stock the tank. If your tank can clear 1 ppm of ammonia in 24 hours, you can stock it in three additions. Start with 40%. If/when you run a week with no ammonia, add another 25%. If you run another week with no ammonia, add the rest. These %s are in terms of the bio-load the fish produce and notthe number of fish. The bigger a fish, the more ammonia it makes.
 
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chrisnolan

chrisnolan

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First- did you outgass your tap water before you tested it for pH? If not you need to retest after doing 1 of 2 things. Let a clean glass of water sit out over night beofre testing or else use and air pump to bubble the water in the glass for about 15 minutes and then test it. You are trying to outgas any excess CO2.

The fishless cycling article here is meant for tanks that contain no or almost no live plants. The more plants one starts out with, the less useful the guide becomes.

Here is why. Live plants use ammonium. They do this way faster than the bacteria can use NH3. So, the more plants one has in any given tank, the less bacteria there will be. However, there will never be no bacteria no matter how many plants one has.

Basically what you are doing is feeding the plants not establishing large bacterial colonies.

Sodium Bicarbonate -

from https://fins.actwin.com/aquariafaq.html

I really need to write the next article re cycling which deals with planted tanks and seeding bacteria to jump start the cycle. Both of these things alter how one should approach insuring that a tank is not in danger of harming fish due to ammonia. When it comes to plants and cycling, there is no way to reduce things to a basic formula the way it can be done when no plants are involved. The reason is due to the great variety of potential plants one can have combined with different planting levels.

Basically. if your tank can clear 2 ppm of ammonia in 24 hous or less, you can pretty much stock the tank. If your tank can clear 1 ppm of ammonia in 24 hours, you can stock it in three additions. Start with 40%. If/when you run a week with no ammonia, add another 25%. If you run another week with no ammonia, add the rest. These %s are in terms of the bio-load the fish produce and notthe number of fish. The bigger a fish, the more ammonia it makes.
I tested the tapwater after leaving it overnight in a glass when I first set up the tank and the pH has been constant for 3 weeks at 6.6 or 6.4. I was advised at the start that I didn't have enough plants to do the silent cycle and to follow the fishless route. Everything was going great until I removed some of the floating plants as they had covered the whole surface of the tank. In hindsight I probably shouldn't have done that as my tests have changed since then. I followed the cycle article and was up to the maintenance addition (dose 3) The next day (day 21) my results were amm 0.25, nitrite 0.25 and nitrate at 20. I then added dose 4 to take reading back up to 3ppm ammonia. 24 hours later amm had dropped to 1, nitrite up to 2 and nitrate up to 40. Still following the cycle and amm and nitrite not at 0 I left it for another 24 hours. Day 23 my tests were zero for amm and nitrite and nitrate still on 40 so I then added the next dose back up to 3ppm (dose 5) Overnight my pH dropped to 6, 1 amm, 0.50 nitrite and 40 nitrate so again I left it for another 24 hours. The next test was the same pH of 6 and that was when I started this thread as I wasn't sure what was happening. I followed the advice here to add the bicarb to raise back the pH and also dose 6 of ammonia as I was still at this stage following the cycle. Today's test was pH 7, 0 ammonia and 0.5 nitrite, 40 nitrate. As amm and nitrite were not at zero but were in the range in the article I went ahead and added dose 7 and hopefully will be good to go tomorrow. I know I need to do a big water change at the end of the cycle to remove any excess bicarb and at that stage I guess I will have to try and remove the algae as best as I can before I add any fish.

It is all very confusing for a new tank owner but have had lots of feedback from forum members so I will keep plugging away and hopefully one day I will have a lovely thriving tank of small community fishes
 

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