Do I need to turn off CO2 supply when lights off??

[Aqua_ikebana]

Hi,

Is it a must to turn off the CO2 supply when lights out??

What is the consequence if I leave the CO2 supply running at a rate of 0.5bps 24/7.

How to test for CO2 over-dose??

Thanks.

[Allen_1971]

At the level of CO2 which you are injecting, there is probabably no risk from CO2 being run 24/7. Assuming you are talking about the tank we discussed the last time.

Typically if you have fish in the tank, they will be the best indicators of CO2 toxicity.

[Plantbrain]

I turn my CO2 off at night. Plants don't need it and that's the only reason I add it.
This is simple to do by plugging the CO2 reactor pump into the same timer as the lighting.

The best way to see if you have enough CO2 is to measure it. Test the pH, test the KH.
http://www.sfbaaps.com/reference/table_01.shtml

Follow the column to your KH.
Add only CO2 to get your pH to adjust the CO2 to 20-30ppm of CO2.

That's a good range. Keep it in this range the whole lighting cycle. That's about it.

Regards,
Tom Barr

[Aqua_ikebana]

opps, sorry for the double posting.

Thanks for the reply.

[cosmos]

----------------
On 2/21/2003 3:49:50 PM

I turn my CO2 off at night. Plants don't need it and that's the only reason I add it.
This is simple to do by plugging the CO2 reactor pump into the same timer as the lighting.

The best way to see if you have enough CO2 is to measure it. Test the pH, test the KH.
http://www.sfbaaps.com/reference/table_01.shtml

Follow the column to your KH.
Add only CO2 to get your pH to adjust the CO2 to 20-30ppm of CO2.

That's a good range. Keep it in this range the whole lighting cycle. That's about it.

Regards,
Tom Barr




----------------

Will a solenoid be required??

[Allen_1971]

----------------
Will a solenoid be required??
----------------

Cosmos,

using a solenoid in conjunction with a timer is the normal means by which we cut off our CO2. While not explicitly stated, I'm pretty sure thats what tom meant.

[sherchoo]

If you intend to leave the co2 supply on during lights out period, some care needs to be observed. CO2 tends to build up from plants and fish respiration. Too much will cause CO2 poisoning whereby you can see you fishes gasping for air.

[Allen_1971]

Sher,

his tank is 120L... I seriously doubt a 0.5bps rate is going to cause any problems even if his tank is heavily planted with a large bioload. The main thing for him is whether its worth investing in a solenoid to save some CO2.

[sherchoo]

Must have missed a the post stating his tank volume... anyway, if the regulator has already been purchased, try 24/7 injection. If the fish is ok with 0.5 bps, you can try a little bit higher.

For myself, I've been using a solenoid regulator since the begining of my planted tank hobby (except the days whereby I DIYed). I thank my lucky stars that one of the fellow members told me that I should get the solenoid type. With much reluctance (due to the cost) I bought myself the solenoid regulator and never have I regreted.

Aqua_ike,
If you do have some spare cash, do invest in a solenoid. It's really worth investing.

[Plantbrain]

Why use a solenoid?

Use a powerhead.

They are much cheaper and have bifunctional benefits.
By turning them off at at night they stop dissolving the CO2, the gas flow still runs but nothing is dissolved it just escapes out the top.

When the pump is on it sucked the gas bubbles in or pushes the water by the gas dissolving it.

You never needed a solenoid to turn the gas on or off.

A solenoid will take about 10 years to make the $ on gas savings since CO2 gas is so cheap. And will the solenoid last that long? Perhaps. They also use about the same electrical as the small powerheads but unlike a powerhead, they do not add any water flow when you need it most, during the day so the plants can have access to the CO2 more.


Solenoids run 40-70$, powerheads run 8-15$.

Regards,.
Tom Barr

[Allen_1971]

Interesting idea tom... Locally, quite a few people use an air pump instead of a powerhead to cause greater surface agitation while the lights are out... This method works pretty well... but the downside is that you need a seperate timer to run the airpump. Your method has an advantage that the powerhead can be tied to the same timer as the lights... Nice []

[Plantbrain]

I hate air pumps. I used one once before I had a good handle on CO2.

Also, when you turn on an air pump, you blow out all that O2 your plants produced all day long. If you do use that set up, wait 4-6 hours before it comes on and stop it 1 hour before the lights come on. Basically anytime the O2 is above or at 100% saturation there's no need for air pumps.

Some slight surface movement is good.
It's mainly an issue of O2.

So if the plants are grown well, the O2 build up duriong the day is pretty high and enough to get you through the night. But if you have a high fish load, this can be an issue.

But if you have a high fish/critter load, you should get a wet dry anyway. These don't drop below about 85-90% saturation values which is good for most all fish and when plants are maxing the O2 levels at 130%-150% during the day.
Regards,
Tom Barr

[Allen_1971]

----------------
On 2/23/2003 10:08:07 AM

Also, when you turn on an air pump, you blow out all that O2 your plants produced all day long. If you do use that set up, wait 4-6 hours before it comes on and stop it 1 hour before the lights come on. Basically anytime the O2 is above or at 100% saturation there's no need for air pumps.
----------------

Tom,

I was under the impression that O2 levels would return to equilibrium (with water at ambient levels) after a couple of hours once the plants stop photosynthesis. Is that why you recommend a 4-6 hour wait?

Also, are there any known advantages of keeping your water at such high levels of oxygenation?

[Plantbrain]

Yes, that's why you don't want to aerate right away. You want to keep the O2.
Higher levels of O2 help breakdown waste, drive bacterial metabolism/respiration faster, more waste are removed and bound. Later at night, there's less organic material to consume the O2, Then if you ever watch your shrimp near the last half of the day, they go nuts on their "O2 high". So fish and critters like all the O2 also.

You can take the high O2 a bit too far and it get toxic likely around 200%+ or more.

Tanks that have high O2 levels can be pruned and replanted with less chnace of algae etc since the waste mulm/detritus that's pulled up removes O2 from the water in large amounts actually. One reason to do the large water change after scraping the algae, pruning replants etc.

Regards,
Tom Barr

[Allen_1971]

Ok that makes good sense... So assuming after 4-6 hours, the O2 levels reach equilibrium. Wouldn't turning on an air pump there help? After all, your O2 levels would be higher than normal.

As an added benefit, I've found that having an air pump causes enough circulation that surface scum rarely forms on the water surface.

Also, I forgot to ask earlier... Why do you recommend switching the air pump off an hour before the lights come on?

[DEA]

why solenoid and not powerhead
let me count the ways

1. powerheads : extra hardware that clutters up with tubing (if external)
2. powerheads take up space in the tank (if internal)
3. good powerheads (read : eheim) are also quite expensive
4. solenoids are small and are readily attached to the regulator
5. solenoids save co2 (at a rate of 5bps and above it's quite significant)

ymmv, of course
whatever works, still works
just that a solenoid is more convenient and elegant

[Plantbrain]

"1. powerheads : extra hardware that clutters up with tubing (if external)"

provided they are inside the tank itself, sumps, overflows etc don' have his issue. i atach cork the pump and plants to the cork and it looks like a green leafy thing instead of clutter.

'2. powerheads take up space in the tank (if internal)

Yes, but not much and see above on using them as plant space/substrate.

"3. good powerheads (read : eheim) are also quite expensive '

7-8$ US for a rio powerhead. I can say the same thing about Solenoids and then they get might costly too.
Cheapest solenoid runs about 40$.

'4. solenoids are small and are readily attached to t"
he regulator '

Yes.

'5. solenoids save co2 (at a rate of 5bps and above it's quite significant)'

Well let's look at this savings.
A tank of gas run about 8-12$ for 10lbs which last about 1 year for 160 gallons of tank maintained at 20-30ppm.

If I save 1/2 during the nighttime i'll save 4-6$ a year.
30$ extra cost for the solenoid means that ~5$ savings a year 30/5= 6 years to pay for itself.
If you want the nicer stuff etc, the cost difference will vary some.

i don't call that significant. and if it breaks, corrodes, fails, which amano, myself and a dozen or so others have had direct experiences with, the powerhead still is an awful good deal. But some points are well taken.

regards,
Tom Barr





ymmv, of course

[Allen_1971]

---------------------

Well let's look at this savings.
A tank of gas run about 8-12$ for 10lbs which last about 1 year for 160 gallons of tank maintained at 20-30ppm.

----------------

Tom,

Just to calibrate your co2 costs... Locally, CO2 top ups costs about US$10 for a 2kg fill (less if your tank is larger)... as a rough guage, you can estimate co2 costs at roughly double that in the $US