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4 hours before lights on to drop 1 point

Joined
6 Jan 2015
Messages
48
Hi all, I've tried for ages now to get the CO2 levels perfect in my tanks. Over the months I have attempted to get a 1 point drop within the 2 hour mark, which seems to be normal for most.

Sadly to achieve this I'm pumping in large amounts of CO2 into the tank, which in turn has resulted in stress to my fish. Eventually I realised that pumping large amounts achieved the 1 point drop, but it just kept going, which led to a drop way beyond 6.8.

So I backed off the injection rate until I achieved the one point drop, then adjusted the timer. Unfortunately this has meant that injection starts 4 hours before lights on! Is something wrong?

Tank 1
200 Litres
Sera Co2 reactor
My resting PH is 7.8
KH 6
Target PH 6.8
4 hours before lights on.
2 x external filters APS 1400 and Ehiem 2217
Wave maker

Tank 2
90 Litres
Inline diffuser
My resting PH is 7.8
KH 6
Target PH 6.8
4 hours before lights on.
APS 1000
Tunze 6010

Both tanks seems to drop at the same rate.

Plants have suffered over this period due to the erratic CO2 fluctuation during testing. I have reduced the lighting in both tanks to try and reduce the stress on the plants. EI dosing as normal.

Everything checked for leaks.

GDA a problem in tank 2

Tank 1 has a yellow/green dusting, which is possibly GDA, also small outbreak of BBA.

Both tanks have a large amount of flow.

Is 4 hours way to early? If so what am I doing wrong?

Thanks
 
I get yellow drop checker 2 hours after CO2 on at 1-2bps in 180l tank, working out about 20gr CO2 a day (hint weigh the CO2 bottle to see consumption).

I suspect you have a CO2 leak, it took me ages (about a year) before I got all the leaks out the system. Every time I got a leak CO2 was either completely randomly variable or monsterous injection rate for b**ger all change in tank CO2 levels. A lot of leaks only revealed themselves when equipment was placed under water and pipes wiggled !!!!

Oh everyone told me I had a CO2 leak, but was convinced I hadn't but CO2 injection rate and plant health and drop checker colour indicated otherwise.
 
I've soaped these to death, any ideas on an alternative method, not sure how I'd be able to submerge test. Seems strange that both are dropping at the same time, would that mean both are leaking?
 
Checked again using soapy water. Everywhere covered and wiggled :thumbup:

No leaks detected.
 
I assume you are running both tanks from the same CO2 source ?

You must split the CO2 as in my picture below, or else you will suffer completely uncontrollable CO2 rates as the CO2 alternately pressurises the system, then depressurised via one diffuser, then the other. (OK assume the one tank in my picture is two in your case).

BigTank2_zps6282955e.jpg
 
I run separate tanks, one for each. Surface agitation has made a big difference I must admit. Learnt that mistake a few weeks back. Definitely improved my erratic co2. Now it's a level 6.8. Just the issue of how long it takes to get there :(
 
Try running a really short piece of newly purchased CO2 tube (you are using CO2 tube ???) straight from CO2 regulator to your diffuser, bypassing everything and sitting and watching the bubbles and behaviour of drop checker/pH. When I did this my drop checker went yellow in less than an hour, fish struggling, which I had never previously seen, indicating an issue with the bits of equipment I had bypassed.
 
I'm using a calibrated pH pen. Cheap one from fleabay but more accurate than the drop checker, which I only use as a visual guide to see if all is well.
 
Did you calibrate it using calibration fluid or the sachets they come with?
 
Yes co2 line used. I could try that. I guess that'll prove or disprove 100% if there's a leak around that area.
 
Strange question, but will co2 leach out of old co2 pipe?
 
Last edited:
Try running a really short piece of newly purchased CO2 tube (you are using CO2 tube ???) straight from CO2 regulator to your diffuser, bypassing everything and sitting and watching the bubbles and behaviour of drop checker/pH. When I did this my drop checker went yellow in less than an hour, fish struggling, which I had never previously seen, indicating an issue with the bits of equipment I had bypassed.

Hi Ian,

Haven't got scales yet so I just (sort of) followed your above advice...

I have an in-line Up atomiser so I took the CO2 tube and bubble counter off the regulator and put fresh tube onto the needle valve (SMC push fitting). I dipped the other end of the tube into a pint (of water!) and observed the bubbles.

I compared this to the original tube with bubble counter and found no difference!

Now I suppose if an in-line regulator was leaking CO2 it would also leak water???

Anyway, I'm still confused, I have an uncountable bubble rate but it takes 2 hours to get a drop of between 1.2 and 1.3 in a 125l aquarium.

As for CO2 running out quickly it's either the regulator, the atomiser or I have just too much surface movement.

It seems like only weighing the bottle with scales can give me the answers I need.

Cheers,

P
 
Other thing is make sure your CO2 tubing as only as long as necessary.

When I first got my CO2 system I cut the tubing FE-> one way valve - > bubble counter as long as necessary, and just used the remaining 3-4m of tubing to in tank diffuser. Idea of long length is so I could move diffuser around the tank as necessary. Fizzed away fine, could control rate no problem, but reality trying to get good CO2 distribution in a large tank from an in tank diffuser just doesn't work.

So I switched to an inline diffuser. Immediately the CO2 bubble rate was uncontrollable and completely variable. Upon watching, what was clearly happening was the 3-4m of CO2 tubing was clearly pressurising up, giving a decreasing bubble counter bubble rate. The bubble rate slowed completely, until the whole system suddenly depressurised, via giant "burp" at the diffuser, bubble rate went manic. Cutting the final tube as only as long as necessary and bubble became infinitely controllable and repeatable...
 
My c02 has to come on 4 hours prior to lights on also to achieve the drop checker colour I'm after, increase the c02 and my checker eventually turns yellow and fish stressed.
I don't see it as an issue either to be honest, there will be many reasons, there is no leak on my system.
 
I achieve lime green. Just the length of time it takes to get there. Guess it's one of those things. If the tanks happy then I suppose I'll have to live with it.
 
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