Fluctuating Kh Levels

[Kiwigirl]

I'm new to planted tanks, I have 2 ambulia plants in my tank, and a fine gravel substrate.

My PH is stable at 7.6

My KH on the other hand fluctuates as follows

4 dkh
5 dkh
6 dkh



Makes the Co2 calculations fluctuate along with it (not injecting at this stage)

Using AMI kits.

Any reason for this to be happening???

 

[Waterloo Kid]

Depends on the timescale over which the readings were taken. If the tests were done one after another then I'd say dodgey test kit. If over a few months then that's life. Water chemistry changes over time, especially as the seasons change. If it was over a few days and no water changes have been done in between I'd say that somethings leaching into your water from the gravel or any rock you have in the tank.


WK

 

[Themuleous]

Yeh I'd say the same as WK. BTW if you're not adding CO2 those CO2 charts based on KH and pH dont work. Only by actually adding CO2 can you work out how much you've got in there. CO2 in the air is around 0.04% so its never going to be higher than that in a tank. Fish breathing adds negligible amounts.

Sam

 

[Kiwigirl]

I've had the kh test kit for two weeks (when I bought my first plant). The readings in my first post span over that length of time.

I have a co2 unit on laybuy at my lfs ($77nz), should have it in a couple of weeks.

Waterloo Kid you meantioned something could be leaching into my substrate or rock, well I don't have rock so I guess the substrate.

Any ideas what??

Do I really need to be concerned??

 

[George Farmer]

I'd guess your gravel contains lime. This will boost KH levels (and consequently pH). CO2 tables take this into account.

Most regular gravels contain lime.

Test your tap water KH. If it's lower then your tank KH you know it's something in the aquarium.

Regular water changes should prevent excess build-up. I used to have 1-3mm fine gravel that boosted pH/KH and no problems.

 

[Kiwigirl]

George Farmer Posted Yesterday, 09:12 PM
I'd guess your gravel contains lime. This will boost KH levels (and consequently pH). CO2 tables take this into account.

Most regular gravels contain lime.

Test your tap water KH. If it's lower then your tank KH you know it's something in the aquarium.

Regular water changes should prevent excess build-up. I used to have 1-3mm fine gravel that boosted pH/KH and no problems.

I tested my tap KH as suggested after 2 drops it came out clear.
Tank KH was 7dkh up yet again.

I did perform a waterchange the 7dkh is the highest reading I've had.

Also did my PH tap 7.2
Tank PH 7.6 which is no suprise to me, tanks usually at 7.6 after 24hrs and remains stable.

Just one thought (thinking outside the box here). I got a new filtration system that is cycling, would that throw things off balance. Like doing more water changes than usual.


Click, I got my new filtration system at the same time I got the kh kit.

I think I may have answered my own question, the filter system has to establish itself, right, so the tank could be off balance.

Or the substrate has lime or something in it.

What do you guys think??

And yes I got cought thinking while typing.