Covers?

[Treefer32]

I'm posting this because I think this is a strange chemistry question related to covers, specifically around air exchange in salt water.

I'm debating going to glass covers for my 340 gallon display. This is going to be a pain for me because I have to scrape the sides of the tank every 2 weeks (I should scrape them weekly) and I have to do with a long scraper because I have wall on the two ends of my tank (it's literally in wall). So, for me, it's going to be a pain because i have to take the tops off. Right now I've got BRS screen covers and the screen rips from the center out. So I need to rescreen them if I'm going to continue with screens or go to glass.

With evaporation my furnace room stays around 50% humidity. I'd like to get that down to 40% to save on electronics in that room. I'm going through about 60 gallons of fresh water a month 2 gallons per day. And I'm on my second dehumidifier in 4 years.

The question I have is related to air exchange. If I put glass covers on, will there still be good air exchange between the sump and display? (I do run a skimmer and algae turf scrubber) plus large amounts of carbon dosing (vodka).

Would the covers noticeably reduce the amount of fresh oxygen being absorbed in the water? I don't know how air exchange works other than surface tension is needed. I run return pump that's exchanging around 2000-2400 gph from the sump to the display, plus 4 gyres mounted at the surface running around 70%-80% power. (Max power is around 5000 ph per gyre).

My ph is consistently running around 8 with the increased vodka dosing, used to get upwards of 8.2 to 8.5.

 

[Dburr1014]

I'm posting this because I think this is a strange chemistry question related to covers, specifically around air exchange in salt water.

I'm debating going to glass covers for my 340 gallon display. This is going to be a pain for me because I have to scrape the sides of the tank every 2 weeks (I should scrape them weekly) and I have to do with a long scraper because I have wall on the two ends of my tank (it's literally in wall). So, for me, it's going to be a pain because i have to take the tops off. Right now I've got BRS screen covers and the screen rips from the center out. So I need to rescreen them if I'm going to continue with screens or go to glass.

With evaporation my furnace room stays around 50% humidity. I'd like to get that down to 40% to save on electronics in that room. I'm going through about 60 gallons of fresh water a month 2 gallons per day. And I'm on my second dehumidifier in 4 years.

The question I have is related to air exchange. If I put glass covers on, will there still be good air exchange between the sump and display? (I do run a skimmer and algae turf scrubber) plus large amounts of carbon dosing (vodka).

Would the covers noticeably reduce the amount of fresh oxygen being absorbed in the water? I don't know how air exchange works other than surface tension is needed. I run return pump that's exchanging around 2000-2400 gph from the sump to the display, plus 4 gyres mounted at the surface running around 70%-80% power. (Max power is around 5000 ph per gyre).

My ph is consistently running around 8 with the increased vodka dosing, used to get upwards of 8.2 to 8.5.

I had covers on my 75 for many years. My sump is in the basement and I never had any trouble. Only 6 fish, one was a purple tang, but, I've had the power go out when I was at work for 5 hours. Only saying this cuz I must of had some decent O2 in the display for no fish to die.
Where is your sump?
Is/will it be turbulent?
Skimmer?
Lots of air gets mixed up with all those things and the travel to the display.

 

[Treefer32]

I had covers on my 75 for many years. My sump is in the basement and I never had any trouble. Only 6 fish, one was a purple tang, but, I've had the power go out when I was at work for 5 hours. Only saying this cuz I must of had some decent O2 in the display for no fish to die.
Where is your sump?
Is/will it be turbulent?
Skimmer?
Lots of air gets mixed up with all those things and the travel to the display.

Sump and tank are in the same room. Not much for surface tension in the sump. However it is about 10 feet from the display tank. 6 feet up and then around 10 feet over to the display. Sump sits on the basement floor (On plywood for a cold / heat insulator.)

Yeah the fish all seem healthy and are find around 20 large rambunctious fish. Also a large 14" diameter skimmer with dc pump running at full power all the time.

 

[Randy Holmes-Farley Verified Community Expert]

I’d be concerned about loss of aeration unless you actively added or removed air under the cover.

I had a similar concern with my basement refugia that were adding a huge amount of moisture to the air. I covered all exposed water and used a bathroom exhaust fan to pull air out from under each cover (5 or 6 44 gallon brute cans) and pumped it outside. That way fresh air was over the water but the moisture went outside.

 

[Top_Lids]

Our experience is that a solid piece lid (like glass) will definitely affect gas exchange. pH a bit as well but in most cases is not problematic. The main thing to consider @Treefer32 with that many fish is it may be better to get a cover with some holes slotted out in it somehow. We use a very specific grade of Polycarbonate for our lids. Something similar should do just fine if the slots are big enough. Bigger investment than glass lids, but the ability to add cutouts is a big plus

Hope this helps