Optimum kH and why plant buble after 30% water change ?

[koon]

Hi,

I will like to ask what is the optimum kH that I need to maintain for my planted tank ?
Is kH high help to dissolve more CO2 or the reverse is true ?

Another phenomenon I observed is no matter how high I pump the CO2,
it will not bubble, but once I change my water (~30%) the bubbe start to stream from my nana like nobody business. Why is it so ?

Tank size = 5 feet x 2feet x 2 feet
Light = 1x150W MH, 5x55W PL
ADA soil
Using one CO2 reactor and another CO2 diffuser.

warmest rgds

[PeterGwee]

If you are not dosing nutrients, the plants would down regulate their growth rate which in turn would affect oxygen production since it's a by product of photosynthesis.

Regards,
Peter Gwee

[koon]

The plant is growing fine.
I dose it regularly with NPK.

However, I just cannot understand why the plant bubble after I change water.
This happen 2-3 times already.
However, for the next day after I change the water, it will not bubble again.

My tank kH ~ 3.
pH ~ 6.5.

Is it due to temperature ?

Or is it after I top up with water, the kH will drop, and the solubility of CO2 in water will increase ?

Really hope somebody can help to explain.

Thnks
rgds

[PeterGwee]

You have a CO2 issue definitely. Unless you are using a drop checker with a reference KH solution, the readings you get for the pH/KH is pretty much influenced by the peat in aquasoil.

Exposure of the plants to the atmospheric CO2 when the tank is drained is the reason why they pearl well after the water change but that stops once the CO2 is not supplied at the same rate.

Regards,
Peter Gwee

[koon]

I am using two CO2 cylinder, is it still insufficient ?

Reactor type ~ 2-3 bubble per second.
Diffuser type ~ 2-3 bubbles per second also.

Is that sufficient for a 5 feet tank ?

Currently, the reactor will fill up with the CO2 air after some time as the water flow not able to fill up the reactor fast enough, does that mean the reactor is not big enough ?
Mine is a two stack reactor.

How do I increase the CO2 level further besides increasing the bubbles/sec ?

Pls advice.
Thnks
warrmest rgds

[lEddyl]

do not think it's WC.
my nana bubble like nobody business everyday once i give it more light.

[uklau]

When I started a new tank 2 weeks ago, my plants also bubble a lot. Almost every now & then I can see a huge bubble being released to the surface from Anubias. C. Wenditi have small bubbles rising to the surface non stop. All these bubbles are from the bottom of the leaves (not from cuts/wounds).

Although both lighting & CO2 remain constant, I'm getting much lesser bubbles now. I'm wondering why? Shall I up my CO2 & fertilizing?

[koon]

sound similar to my scenario, after change water, the plant will bubble.

i tried to double my CO2 bubble after that, the nana will not bubble at all.

just do not understand why.

[blackBRUSHalgae]

I would guess that your tank's water circulation will be none during water change, assuming that your filter or any water pump is turn off during water change. If that is the case, O2 bubbles will appear as the already oxygen-rich water column along with no water circulation will cause O2 oversaturation in the stagnant water column.

you can conduct a simple test to verify this. During photo period, simply turn off all your filters or any devices that causes water movement, and observe over a period of 1/2~1hr.

[koon]

No.
The filter is still on cos it is only 30% water change.
Water turbulence is a lot since after draining off, need to top up again.

[morta_skuld]

i have a tank that has a minimal pearling but the growth is good. I dont think if the plants are not pearling it isnt right. as long as it grows good then you are on the right track. just my opinion.

about the water change blackbrushalgae is right. its an oversaturation of o2. But it is an exhaustive process to the plant does not necessarily means that it is really pearling healthy.

[koon]

understand...just want to understand technically what happen.

anyway, thnks everybody.