" wrote in message
m...
Why not do this.

Use DIY CO2.
This will save you a great deal of time messing with it.

It might, but I'm not prepared to take the risk that an exploding bottle of
gunk sprays over my livingroom, OR that I end up with gunk in my tank, from
something going wrong. Ta for the suggestion, but I'm NOT going the DIY
route.

Next take a small tiny powerhead, and have the out put of the DIY
bubble into the suction side. Use a rigid juice bottle for the DIY
container.
Plug the powerhead into the lighting timer.

When the lights come on and the plants use the CO2, the gas gets
dissolved and adds it to the tank. When the lights are off, no CO2.

This isn't the problem. I *have* CO2 in the tank just fine - the air pump
used to go on with the lights, off with the lights, and therefore the water
wouldn't pass through the reaction chamber at night.

But O2 is directly linked to plant production.
If you have high plant growth, you get high O2 production in your
tank.
So if you grow the plant well, you have sky high O2 levels.

Yup, my plants are growing at a phenomenal rate, and pearling (see my
earlier post).

These levels should last through the night fine.


Should, but aren't. I know they *should* - but my question was, in a VERY
heavily planted tank, there are both fish AND plants using oxygen during the
night. I'm obviously getting o2 saturation during the day, but I'm
wondering if the volume of plants is leading to depletion during the night.

Add more circulation and have a slight surface movement. No surface
movement IMO is bad.

Regards,
Tom Barr

I *have* surface circulation. When I drop food in, it gently swirls from
one side of the tank to the other.

This morning, I have moved the spray bar of the cannister filter to increase
this current slightly. We'll see how it goes.

Velvet