Preventing Sump Evaporation

[paulthomas]

Would floating a sheet of EPDM in a sump or simply covering a sump with it prevent evaporation? It's supposed to be inert and lasts for years. Plus I can get it from a friend of mine who is an industrial roofer.

 

[NateHanson]

Make sure it won't get sucked onto any pump intakes! I'd probably prefer something like starboard or even just acrylic, cut to an inch smaller than the water surface, and float that. You won't have trouble with it flapping around in the current.

Keep in mind that something like this will decrease heat-loss from your sump (because evaporation absorbs heat from the water when it turns to vapor). You'll also have a little less gas exchange. So make sure your tank isn't on the verge of overheating, and make sure you have plenty of aeration going on elsewhere (skimmer should do this just fine).

Nate

 

[paulthomas]

Thanks Nate. In your opinion, is it worth trying one of these covers? I'm expecting a call from a company that specializes in preventing water evaporation. Unfortunately some of their better methods appear to be expensive and/or not condusive to keeping fish/corals... alive.

I was thinking that there'd be enough exposed surface area in the display and the skimmer section. Both will be uncovered and there should be plenty of turbulence in both the display from three Vortechs and in the sump from two drains dumping into the skimmer section.

 

[NateHanson]

I think heat is the big question. Are you trying to reduce evap to keep humidity down?

I wouldn't think aeration would be a problem as long as the skimmer is running.

Maybe it would be more effective to just have a cover for the sump, with a cutout for the intake and cup of the skimmer (so they get fresh air).

You may just need to have a humidistat with exhaust fan even with these measures. I really don't know. Probably need advice from people with big tanks.

 

[paulthomas]

Good idea on the humidistat and fan. I saw someone's build, he had two energy star rated fans for this reason.

I want to reduce evaporation to keep RODI costs down. But I need to dissipate heat in the summer too. I don't know where the balance lies, I guess I'll just have to learn by trial and error.

Venting is really important in the basement too. There's a de-humidifier in the main room from the previous owners that had really old water in it. Nasty. But we haven't had a need to use it ever. I suppose it was used on really humid days some years ago. But with the sump in a relatively small room, I need to make sure it's properly ventilated, especially since there are pipes there.

Crap. I just realized that there are a couple feet of copper pipe for the outdoor sprinkler system. I should wrap those. The rest of the pipes in the open are cast iron. The large pipes stemming from the boiler are covered in asbestos. But those are going to be wrapped soon. The others are cold water pipes (indoor sprinkler head too) that I was going to spray with Rustoleum or something similar.

 

[rjdudek]

EPDM from a roofer will almost always be toxic. Roofing EPDM has chemicals added to retard mold and fungus. There is a good reason Firestone PondGuard is marketed under a special name.

If you are using a Rubbermaid tank they sell elastic covers at feed stores. Made from plastic and tyvak

Some of our customers float evap spheres in their chemical tanks to cut evap. They are nothing more than ping pong balls. They float so they stay out of the drains. For a sump you would have to look at where they might get in an intake. You can still add chemicals and reach into the tank as necessary. Something to think about.

 

[alpha0r]

I think heat is the big question.

Yep.

Maybe it would be more effective to just have a cover for the sump, with a cutout for the intake and cup of the skimmer (so they get fresh air).

If I wanted to stop evap I would go with this. Although the ping-pong balls sound intriguing. If something doesn't touch the watter you have less concern about impurities. Plus you know that glass/acrylic are safe and fairly inexpensive.

I want to reduce evaporation to keep RODI costs down.

If you have your own RO/DI unit these costs are negligible.

Boosting your evap also allows you to add more Kalkwasser. If you can meet your calcium demands this way you will save big money instead of getting a calcium reactor.

 

[paulthomas]

EPDM from a roofer will almost always be toxic. Roofing EPDM has chemicals added to retard mold and fungus. There is a good reason Firestone PondGuard is marketed under a special name.

I meant EPMD, EPMD! What's EPDM? Eric B. and Rakim will cover the RODI container. Buying it in bulk is not a good option. My buddy would most certainly give me a small sheet for free, which is why I asked. But that makes sense. I'll probably pass on that idea to be on the safe side.

I've got a brand new 100 gallon RM stock tank. But I'm probably going to stick with the pond liner.

The evap. spheres sound like a great idea, but would they act as bio-balls? I want a reef, not FO. That's a lot of surface area with a big section of the sump loaded with spinning plastic balls. Plus they'd get a little gunky after awhile and having to clean them individually might be a pain. It's a good idea though.

Thanks rj.

In regards to the huge surface area of this pond liner. It's not much greater than the RM 100 plus another good sized container for a RDSB or fuge, say. I don't remember the dimensions of the RM, but it's certainly a large container. What I like about the pond liner is that it will provide close to 6' of linear flow plus enable me to keep everything in one container once it has baffles.

If I wanted to stop evap I would go with this. Although the ping-pong balls sound intriguing. If something doesn't touch the watter you have less concern about impurities. Plus you know that glass/acrylic are safe and fairly inexpensive.

I don't want to do glass, as it'd be heavy and could break. Plus I've got two kids. Acrylic and polyethylene (which wouldn't be cheap) will warp and sink. But I wouldn't be getting air tight coverage anyway. A couple pieces of 1" dense foam insulation on top of the sump might work OK too.

I understand I may shooting myself in the foot by trying to save on top-off water (retaining heat with the water in summer). I'll figure it out as I go. But I wouldn't say that the costs of running an RODI are negligible, especially combined with my quarterly water bill. At a 3 or 4:1 rate, the bill would get pretty high with a total volume of 350+ gallons in the system.

I was going to skip on Kalk and use a Ca reactor. I plan on a good number of SPSs, more than 50%, so the Ca reactor is inevitable.

Thanks,
Paul

 

[alpha0r]

I don't want to do glass, as it'd be heavy and could break. Plus I've got two kids. Acrylic and polyethylene (which wouldn't be cheap) will warp and sink. But I wouldn't be getting air tight coverage anyway. A couple pieces of 1" dense foam insulation on top of the sump might work OK too.

What are the dimensions of the sump? You could always put a brace don the middle to keep the cover from slumping. I guess you could just leave the thing off during the summer to solve the heat issues.

 

[paulthomas]

Thanks alpha. Yeah, that sounds like the best route. Tinkering with putting it on, taking it off, putting it on... is porbably not a good idea. But I'll leave it on in the winter and insulate the outside of the sump to keep heat in.

I just checked the dimensions again, should've written it down the first time. The opening measures 72 x 36. It tapers to 68 x 30 at the bottom. It's got a depth of 18", a 3" lip around the perimeter and it's made of fiberglass.