Plumbing for converted Wet/DRY – CO2 loss?

[braddiamond]

I have read many threads on this, but I can’t find the specific situation that I have. <See 2 images attached>

I want to make sure that I am not losing too much C02 b/c of my setup. Unless I crank the C02 up really high so I can’t count the bubbles, the drop checker stays at blue with a hint of green.

I have a glass cover on top of tank and my wetdry also has a plastic top that covers 99.9% of it.
The overflow has a Hoffman gurgle buster and the ”drop” into the overflow box is about 1 inch. It then goes thru the HGB directly to the wetdry, via tubing which is a straight drop. The end of the tubing goes about 2 inches below the water surface. There are a lot of bubbles that come out of the tubing and sometimes it starts to “crawl” back up the tubing. I have added some more foam at the bottom but it does not seem to do any good.
1) Are the bubbles the center of my issue?
Is the normal?
Or unfixable with my setup
Any other factors: Is the MAg7 too much flow, Too much light, More foam?

Please advise what I can do to fix my C02 issue. Feel free to ask me to clarify anything. THANKS!!!!!

My Setup
72 Gallon with an overflow
Overflow has a Hoffman gurgle buster
Overflow goes to the Converted Wet/dry
Wetdry has sponges and a Mag7
CO2 tank with GLA regulator sends CO2 into MAG7 with a Fractionating Impeller
Mag7 is the return, sends water and C02 to tank.
Lighting is 4 CF bulbs 55 watts each. 1 set (of 2) is on for 8 hours, second set (of 2) is on for 4 hours in the middle of the 8 hours.
CO2 is on for 8 hours (same as light) at a rate of about 4bps.
Cal Aqua Labs drop checker

[HD Blazingwolf]

THE BUBBLES are ur issue. u need to either crank the c02
or build a top that u can attach the tubing to and seal that secion off
see attached picture

BLUE. --- BIO BALE
RED ---- DRIP PAN, Mechanical padding
yellowish green --- water lvl in media area. lower fom having pressure build to sealed sump
green ---- water lvl in pump area



the drip pa has been sealed at the top to prevent c02 loss. if i take the tape off. water lvl rises in the media area and c02 gets burned off FAST

[Kathyy]

4bps seems low for a 72 gallon tank. Try nudging it up a bit every couple days watching the fish more than the drop checker. Drop checkers can take a couple hours to show more CO2, fish can die in a couple minutes of adjusting the CO2.

I just put a new HOB overflow box on my tank with 2 outflows so I can do a Herbie type system and now have no bubbles in the sump. I do think I have more CO2 staying in the system now so bubbles might be an issue. Can you seal up the wet dry part of the sump?

I would start and end the CO2 an hour or so before the lights go on and off too unless you know your needlewheel system and pump are getting CO2 all through the tank in a few minutes.

How is the circulation in the tank with your pump? Can you see water movement throughout?

[isu712]

I don't have experience with wet/dry sumps, but my guess is that your problem is contact time between the CO2 bubbles and the water. Do you see bubbles coming out of your return? This would be evidence that contact time is the issue. If this is the case, you may want to consider putting a CO2 reactor between the Mag7 and your return. A reactor can be purchased or built out of PVC pretty cheaply.

[braddiamond]

Thanks for the quick replies.

>> HD- The W/D is completly sealed, both left and right side. The picture you see, the foam is actually on top of the cover. You dont see condensation b/c i just had it opened. Does the encloser keep the CO2 in and it gets "reabsorbed" into the water. That is what i thought and cant figure out why i still have an issue. Is it ok that the water just drops thru the tubing into the sump? Are the bubbles created by the HGB or other factors?

>>kathyy- 4gb- i can try the nudge, but the tank is filled with bubbles. Already unsightly. The flow is great i see the bubbles all over the tank. Lighting i can adjust but this would not really affect the C02 levels in the middle of the 8 hour cycle, correct?

>>isu712- I think the MAG7 with a Fractionating Impeller does the job of the reactor and there are a crazy number of bubbles throughout the thank.

Any other thoughts?
Thanks

[DiabloCanine]

Do you have a picture of your overflow?......DC

[braddiamond]

I dont have a pic with me but....see the 2 pics below that i just borrowed from web.
I have the same overflow box sans the durso.
Cut the top off the durso and replace it with the HGB and that is what i have. The drop from the teeth of the overflow into the "main area" of the overflow is only 1 inch.
Thanks

[DiabloCanine]

I am not familiar with that overflow pipe, I use a durso setup with no problem. Just curious how much your sump fills up with the pump turned off. 700 gph may be a bit much for a 72 gallon and will contribute to the outgassing; more flow = more bubbles = more outgassing; but in my book more flow is better for the habitat. Might want to look at diffusing your CO2 a different way; I found the reactor used in my sump (cannot remember the name right now but pics in my 110 link below) works best for my application. I am sure most outgassing takes place in my sump but diffusion is certain (turns on/off with a PH controller) and CO2 is cheap in my world. I wouldn't worry so much about the bubbles and focus more on better diffusion. Might be that 24 hour diffusion could be the answer or using a PH controller.....DC

[braddiamond]

the sump only fills up a little as the overflow pipe is almost to the top of the overflow. besides a smaller pump what a way to slow the flow?

[DiabloCanine]

Originally Posted by braddiamond

the sump only fills up a little as the overflow pipe is almost to the top of the overflow. besides a smaller pump what a way to slow the flow?

I do not think I would choke a Mag Drive; they are designed to push and choking it might cause premature wear. One way to slow flow is to use an inline CO2 reactor but I do not think it would be pratcical connected to a 700 gph pump. Why don't you try having your CO2 run 24/7 for a while to see if you get improvement.....and/or invest in a diffuser for the sump.....and/or invest in a PH controller and have no worries?......DC

[HD Blazingwolf]

it doesn't get reabsorbed to say. however with it sealed what does come out of solution builds up pressure in the media area. because the partial pressure of c02 is raised in that area over time, c02 doesn't leave solution as well

it just helps keep what u have injected in the water, in the water so to speak
i've taped 13 different times, and have found a method that works best because after too much pressure builds, it blows the seam out and its all wasted so u have to have a good seal but enough play in the seal that it can allow pressure to blow off without compromising the integrity of the seal

u can hear a slight hiss about every 5 seconds in one corner of my sump.. if i push it down all the water drains out of the media section until it opens up another portion of the tape seal

in case i didn't make it clear, the seal is the black electrical tape that goes around the top

[braddiamond]

I have upped teh BPS a little. Ill know when i get home tonight.

I appreciate all teh reponses i just dont want to complicate my setup.

Im thinking , I shoudl try to lower my flow rate in hopes to allow for more CO2 "absorbtion" and less splash in the Wet/Dry. Does this seem like a good plan??

If so can i test it out with a ball valve on the return, as may mag7 does not have anything built in. Even if it shorten its life it will give me an idea of what direction to go in.

From what i read a Mag 3 w/Fractioning Impeller should do the job. The head is the normal 3 to 4 ft of a regualr tank stand.

Any thoughts?? Thanks

[30king]

I have a set-up almost identical to yours, but on a 90gal. Sealing the lid on the sump will help a little, but you (and I) have a passive overflow that draws in air. This is different than Blazingwolfs. His is based on a siphon at the top, without drawing much air in.

You can minimize, but not eliminate CO2 loss. Its not that big of a deal. You need to up your CO2 to about 6 bubbles/sec, slowly and read your plants. Injecting CO2 is about perpetual CO2 loss; accept this and you will be happier. I spent a lot of time sweating every bubble that made it to the suface. CO2 is cheap; and a cost of doing business.

Below is a descript of my set up and how I reduce loss and improve CO2 water absorption.

My sump is almost the same as yours. I use bioballs in my chamber, with a drip plate on the top of them. I have a course filter pad on top of the drip plate to act as a prefilter. I change it every 1-2 wks. My overflow intake spills right onto the filter pad. Just like old school salt water trickle filter. I keep my sump filled as high as possible. This helps. I seal the lid with duct tape; this helps. Your overflow intake going below the water isnt't helping much, and makes prefiltration harder. The water falling through the tube is where all the CO2 loss occurs, and the top is open to air. This is the only bad part of our set up.

Like you, i keep my overflow elbow up high so water only drops about an inch. Again, CO2 is lost when the water travels down the drain tube. Nothing we can do about this with our set up; and not worth the effort.

I initially injected CO2 into my needle impellor. this pump is also my sump return. You get lots of microbubbles. I have a PVC reactor inline after the pump. It is a 3" wide 20" tall beast. It did not catch very many micro bubbles. I went extra wide hoping an eddy could occur inside, catch more bubbles; no luck. I now inject my CO2 right after the pump and before the reactor. I noticed about 60% less bubbles in the tank. my drop checker still goes from dark blue to very light green in about 2 1/2 hrs. I have good plant growth. I use a ball valve on the return to reduce the overall flow into the sump and to slow the return through the reactor. Its about 3/4 open on a 700gpm pump. this has seemed to help. I direct the outlet flow toward the bottom/ opposite corners of the tank using those Y-flex nozzles, and use a Hydor for tank circulation

If you have a good plant load, a high bio filtration is not as important regarding the volume going through the sump. My sump at 50% probably filters better than most canisters, IMO.

higher light if you want aggressive growth, less light for slower growth. I dose EI, and add a bit of excel at weekly water change.

hope this helps. give me a yell if you have any questions, or want pics of my set up.

[DiabloCanine]

Originally Posted by braddiamond

I have upped teh BPS a little. Ill know when i get home tonight.

I appreciate all teh reponses i just dont want to complicate my setup.

Im thinking , I shoudl try to lower my flow rate in hopes to allow for more CO2 "absorbtion" and less splash in the Wet/Dry. Does this seem like a good plan??

If so can i test it out with a ball valve on the return, as may mag7 does not have anything built in. Even if it shorten its life it will give me an idea of what direction to go in.

From what i read a Mag 3 w/Fractioning Impeller should do the job. The head is the normal 3 to 4 ft of a regualr tank stand.

Any thoughts?? Thanks

Choking your pump is never a good idea; unnoticed pump failure can kill all your fish. If you are going to spend money consider something like this http://www.marinedepot.com/Red_Sea_C...FICORA-vi.html to put in your sump.....DC

[30king]

diablo- I have to disagree somewhat. Reducing waterflow does not hurt the pump unless you are restricting almost all the flow, IMO. Every pump I have ever owned has come with a few sizes of output barbs for Different size hoses. Using the smallest barb (and comensurate hose size) supplied by the manufacturer is reducing flow right there. My current pump came with a 1" thread and reducers down to 1/2". Some pumps come with a built in flow adjuster (Eheim comes to mind). As long as the impeller has the ability to push some water out, I don't see much of a problem; esp a submerged pump that can disperse any heat build-up.

Just my thoughts