C02 levels fluctuate too much on WC day

[Keetchy]

Hey guys. Some of you know I'm having a bit of an issue with algae at the moment so getting my C02 stable is the first task.

On WC day I try to get it done before the C02 is timed to come on. So I don't have to interrupt the C02 getting pumped into the tank. Even though the tank is fully filled up and running again before the C02 comes on, by the time the lights come on the DC is a bluey green colour. Then by the time the C02 turns off, it's a lime green colour. But on non WC days the DC is a lime green colour when the lights come on.

Is the reason for this because I've taken out at least 50% of C02 rich water and replaced it with fresh non C02 water? If this is the case, does this happen to your tanks on WC day?

Surely this will be affecting the balance of the tank for that 1 day of the week which isn't going to help me get to the bottom of the algae issue.

If this isn't right, any tips and advice would be much appreciated

 

[erwin123]

plants actually get access to CO2 during water change day when the plant tops are exposed temporarily to the air and get "non-limiting" amounts of CO2? After all there is a 10000 fold lower diffusion coefficient of gases in water, compared with in air, and submerged leave have even thinner membranes to allow for easier CO2 diffusion?

 

[erwin123]

Here are experts weighing in on CO2 and water change:

Tom Barr:

CO2 after water changes and an experiment

Many suggets that the pearling we often see after a water change is due to air/O2 and other gases such as N sticking to plants and is not true O2 pearling. There are a few ways to address this to see if it is in fact "increased growth" or just sticky bubbles (This arguement has merit and must...

barrreport.com

Clive:

co2 and water changes

in a low tech tank very infrequent water changes are recommended on the basis that exchanging water causes fluctuations in co2. i know there is a tom barr piece of work that shows fluctuations in co2 resulting in increased algae growth. (i think this was in a high tech tank experiment??? or is...

www.ukaps.org

 

[Kezzab]

Hi, my gut feeling is that if you have algae problems its unlikely that this apparent water change day fluctuation is the cause.

In my own tank I do 50% wc a week, plant health is good, no algae to speak of. Hundreds of other people do the same.

I've had weeks where co2 has stopped for a few days before I noticed, with no bad impact.

I would be looking at your co2 injection, the flow, cleaning regime, and your nutrient dosing first.

If you are convinced wc is the issue, just leave your lights off that day would be the simplest response.
K

 

[Keetchy]

Thanks for your replies guys

So I don't think my algae issues is caused by WC day, the algae started when I added a 2nd light so has put the balance of light/C02/ferts out of line. I'm slowly trying to get this back in balance. But was worried that this 1 day a week of fluctuating C02 isn't going to help me get back on track. It is only on WC day that the DC is a different colour when lights come on so I'm hoping that 1 day out of the 7 shouldn't have so much of an impact on the tank.

Unfortunately I am not able to change the times of C02 for separate days, my timer is not that efficient. Lol. Its the same times for all days.

My surface agitation has just changed as of yesterday as I have now fitted a skimmer lily pipe set. As for C02 times, I had it set to 2 hours before lights on and 1 hour before lights off.

I found the start of Clive's post very useful, I will have a proper read of that later on in the day.

Again...... thanks for speedy replies