# 800L w/ sump: CO2 tuning



## Costa (25 Oct 2019)

Gear:

- 800L (700 DT +100 sump)
- 5KG CO2 cylinder
- CO2art PRO-ELITE reg
- Sera Flore CO2 reactor 1000, on a separate 2000 LPH pump

I used to run my CO2 at around 2-3 bps 24/7. I didn't get any pearling but assumed that "some CO2 is better than no CO2". I decided to try and optimize CO2 uptake and so I purchased a drop checker last week. With exactly the same settings (24/7, 3-4 bps) the drop checker colour has been a nice dark blue for the past 3 days.

This morning I upped CO2 to approximately double (can't really count the bubbles/sec) and 6 hours later I don't think the drop checker's any different, maybe a lighter blue? But I may be biased...

Target is to get a green reading on the drop checker and then set the CO2 to start 2-3hrs before lights on, as opposed to 24/7 that it's running now.

Any ideas, suggestions, advice very much appreciated!


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## ian_m (25 Oct 2019)

For 800l and a "CO2 dissipating" sump you will need an absolute monster injection rate, possibly even more than one injection point, in order to even get the slightest change in a drop checker. See Zeus's tank on how to achieve correct levels of CO2 injection in a 500l tank.

https://www.ukaps.org/forum/threads...le-fixed-excellent-after-sales-service.43046/

Try measuring your pH (using pH pen) before your CO2 turns on. When lights come on, you should be aiming for a one unit drop in pH.

If you have no fish, you can try absolute monster levels on injection, to see if you can shift your drop checker off blue.


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## Zeus. (25 Oct 2019)

Here's the vid of my BPS on 500l



The one at the front is on for whole CO2 period and the one at the back is on for pH drop only.

Think I would increase your BPS, do you have a pH pen?


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## Costa (25 Oct 2019)

Yes thank you Ian, Zeus - I have studied your thread and the key difference is your FX5 vs my sump. I am not at all sure if I will ever get to a green drop checker with all that off gasing, let alone hitting green right before lights on... It's almost impossible to count bubbles after 7-8/sec so where I am at the moment is turning up the needle valve by a few millimeters at a time, wait for 3 hours and check the drop checker colour. Is this a good plan?

Note that both the DT and the sump have covers (with the necessary holes for tubes etc of course).

Tank & Sera Flore shots: (some algae on glass)









I do not have a pH pen I'm afraid, I have kH and pH test kits (seachem and Sera respectively) thought. Because at the moment the CO2 is constantly on I didn't see the point in measuring these parameters but I can easily do.


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## ian_m (25 Oct 2019)

Costa said:


> I do not have a pH pen I'm afraid, I have kH and pH test kits (seachem and Sera respectively) though.


You need to use a pH pen as hobby grade test kits are really not up to anything much (except emptying your wallet) when testing water containing numerous ionic substances.


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## Zeus. (25 Oct 2019)

Costa said:


> I am not at all sure if I will ever get to a green drop checker with all that off gasing, let alone hitting green right before lights on...


'

Well @Filip Krupa doesnt have a problem with CO2 and the 2000l beast and sump

CO2 used Database has the link to his 'nano lake'


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## Zeus. (25 Oct 2019)

Just checked my CO2 database thread and Filip is using more then 50% less CO2 per hour per litre


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## X3NiTH (25 Oct 2019)

I would increase the efficiency by adding an inline atomiser and feed that to the sera so there is already micro bubbles in the water rather than waiting for the reactor itself to form them. I would also try to seal the sump more securely rather than just covering it.


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## Filip Krupa (25 Oct 2019)

Zeus. said:


> '
> 
> Well @Filip Krupa doesnt have a problem with CO2 and the 2000l beast and sump
> 
> CO2 used Database has the link to his 'nano lake'



Correct! Sump off-gassing is not a problem for me. However, I have designed the system so that minimal "waterfalling" happens.
Hope this makes sense

Fil


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## Costa (25 Oct 2019)

Filip Krupa said:


> Correct! Sump off-gassing is not a problem for me. However, I have designed the system so that minimal "waterfalling" happens.
> Hope this makes sense
> 
> Fil



It does make sense and thanks, but I also noticed that you burn through 6.5kg of co2 in 2 weeks!!


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## Costa (25 Oct 2019)

X3NiTH said:


> I would increase the efficiency by adding an inline atomiser and feed that to the sera so there is already micro bubbles in the water rather than waiting for the reactor itself to form them. I would also try to seal the sump more securely rather than just covering it.



Thank you. Do you actually think this will help? I can't see any bubbles escaping the Sera reactor


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## Filip Krupa (29 Oct 2019)

Costa said:


> but I also noticed that you burn through 6.5kg of co2 in 2 weeks!!



That’s due to the size of my system (2,150+ L), and not so much the injection rate per 1L of water. There are plenty of peeps on here that easily inject more than double per 1L than I do.


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## Edvet (29 Oct 2019)

I used low dose 24/7 in my sumped 400 gallon with (lots of) succes. Indeed a bit is better then non. I used 2/3 bps entering 1) through the pipe wich caried the sump return and 2) on a separate diffusor ( glas spiral and a plastic dennerle thiingie running on a sepatate pump).


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## Costa (9 Nov 2019)

Got myself a drop checker, tested my CO2 for 3 weeks, didn't move from v. dark green (borderline blue to be honest...) Problem is the flow into the sump was at 90 deg and created a lot of O2 bubbles (waterfall effect per @Filip Krupa). I modified the PVC tube that drives the water into the sump but adding a 45 deg elbow and some PVC flexible tubing after that and  managed to reduce the O2 bubbles by ~ 80%. I set the CO2 at 3 bps and I'm monitoring the bubble checker. I'm not very optimistic I have to say but I had to try it.


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## Costa (10 Nov 2019)

Thanks to your advice my plants started pearling around 1 hr after lights on yesterday. Very happy as this is the first time I had pearling in my tank. CO2 was at 3bps, but the drop checker was still light blue maybe borderline dark green.. I fine tuned the water flow into the tank a little bit again this morning and now I have no bubbles at all from the water coming into the tank - I tuned down the pump (max speed10k LPH) to ~20% and I hope the 3400LPH wave maker will provide enough flow. I also upped the CO2 to ~5bps. There is flow across the tank, not as strong as before when the pump operated at 85%  but all plants are moving, except for the L. brasiliensis that's too short. I will post a video at lights on later today.
Thanks again!


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