Fluctuating KH

[Aktasak]

Hi! I’ve been having some problems with my KH, it seems to be fluctuating. At one point it was at 10, got it to 7 and then throughout the week it creeps up slowly. At this moment my GH is 7 and my KH is 7 but I want my KH lower than the GH and to stop fluctuating. I use remineralised RO using Seachem Equilibrium and Alkaline Buffer, at this point I’m only using Equilibrium to buffer my GH and nothing for my KH in an attempt to fix the issue.

The tank houses a betta so I want the parameters perfect for him as well as some Corydoras.

The tank has JBL aquabasis plus as the bottom layer capped with sand, I am suspecting the aquabasis may be raising the KH as I cannot think of anything else that is raising it.

Thanks!

 

[MaloK]

You nailed it. the clay in the substrate is acting as a natural buffer.

If you have a small tank and have a substantial quantity of aquabasis. Depending on how densely the tank is planted, It can influence KH for a while before stabilizing.

 

[Jinx_]

Hi! Welcome to the forum!
Trust me, you will get the best advice on here!

It can influence KH for a while before stabilizing.

How long would this last? And does it affect the stock in any way?

 

[Aktasak]

You nailed it. the clay in the substrate is acting as a natural buffer.

If you have a small tank and have a substantial quantity of aquabasis. Depending on how densely the tank is planted, It can influence KH for a while before stabilizing.

Interesting, I thought clay was inert ! The tank is quite densely planted, I’ve attached a photo for you! It’s a 10 gallon shallow tank, has a ridiculous amount of vallisneria and some hygrophila species!

How long would I have to let it “settle” it has been set up since the beginning of September.
Thank you!!

 

[MaloK]

Interesting, I thought clay was inert ! The tank is quite densely planted, I’ve attached a photo for you! It’s a 10 gallon shallow tank, has a ridiculous amount of vallisneria and some hygrophila species!

How long would I have to let it “settle” it has been set up since the beginning of September.
Thank you!!

Yes, you're right clay is pretty inert, but the one you have in your aquabasis as been enriched with nutrients.

 

[Aktasak]

Yes, you're right clay is pretty inert, but the one you have in your aquabasis as been enriched with nutrients.

It’s my first time using a substrate like this so I wasn’t really sure what to expect. Though spoke to JBL themselves and they told me if it’s capped, it would not affect water chemistry which is weird because even though it’s capped it’s still in the water column.

I’m hoping it stabilises soon as the fluctuations cannot be good for my livestock!

 

[MaloK]

How long would this last? And does it affect the stock in any way?

Difficult to say how long it will "over" leech. But it's a good thing to keep it in check and try to prevent swings.

It’s my first time using a substrate like this so I wasn’t really sure what to expect. Though spoke to JBL themselves and they told me if it’s capped, it would not affect water chemistry which is weird because even though it’s capped it’s still in the water column.

I’m hoping it stabilises soon as the fluctuations cannot be good for my livestock!

Looks properly capped to me, I think things should straighten up quickly after a couple water changes.

 

[Aktasak]

Difficult to say how long it will "over" leech. But it's a good thing to keep it in check and try to prevent swings.



Looks properly capped to me, I think things should straighten up quickly after a couple water changes.

Should I continue with just using the GH buffer and no KH buffer? I do a roughly 40% water change every week and because my tank currently lacks a lid…I top up a couple of times during the week with pure RO.

 

[MaloK]

If you do large water changes at a fast enough pace that there is minimal swing in KH over a week, I would not add any more buffering agent until it starts to lower between water changes.

If there is a big discrepancy between your source and tank water, You could go with smaller water changes more often for the time being. Or add a little KH+ to prevent a drastic shift in the tank.

 

[Aktasak]

If you do large water changes at a fast enough pace that there is minimal swing in KH over a week, I would not add any more buffering agent until it starts to lower between water changes.

If there is a big discrepancy between your source and tank water, You could go with smaller water changes more often for the time being. Or add a little KH+ to prevent a drastic shift in the tank.

I do water changes every Sunday; for example last week my KH was at 7 and by the time I prepared for a water change on the Saturday it was at a 9 so it’s not a HUGE difference but it’s still slightly annoying!

My source water is RO water, I don’t use tap at all.

 

[MaloK]

Between 7 and 9 is a 25% difference, it's enough to consider.

Continue to top off with pure RO and use remineralized water that is near consistent with the results you want to maintain.

It might be iffy at first, but don't cut back with pure RO if KH is too high, use water with the target parameters or slightly lower. With time fluctuation will regress at every water changes.

During this, the plants should start to put your substrate at work and start to consume the mineral over flow.

 

[Aktasak]

Between 7 and 9 is a 25% difference, it's enough to consider.

Continue to top off with pure RO and use remineralized water that is near consistent with the results you want to maintain.

It might be iffy at first, but don't cut back with pure RO if KH is too high, use water with the target parameters or slightly lower. With time fluctuation will regress at every water changes.

During this, the plants should start to put your substrate at work and start to consume the mineral over flow.

So remineralise using GH and KH buffers to my target parameters for water changes and hopefully it’ll settle? From what I understand from your message.

I’ll keep doing top ups with RO as normal.

 

[MaloK]

Yes, it will take more time to balance between water changes, but the transition will be smoother for the fish.

If KH rise too fast you can do small 10% water change with Seachem Equilibrium only, everyday to prevent KH from rocketing if needed.

 

[Aktasak]

Yes, it will take more time to balance between water changes, but the transition will be smoother for the fish.

If KH rise too fast you can do small 10% water change with Seachem Equilibrium only, everyday to prevent KH from rocketing if needed.

Thank you! You’ve been very helpful, I’ll definitely see how it goes. Last resort I was going to strip the tank completely and use a different bottom layer but most are clay based so I’d like expect to have the same issue? But this stuff grows my plants so so well.

 

[MaloK]

Oh no, be patient, At some point you will also start to add liquid fertilizer to compensate. But your setup will be wonderful in the long run.