Reef Pilot's Undersea Oasis

[Reef Pilot]

I have acrylic lids for my upstairs tank, and lexan covers for the downstairs one. Lexan is better because it doesn't warp, and you can use thinner materials (1/16"). Also, it has very good light transmission, which is why they use it in commercial greenhouses.

I know there is some controversy about gas exchange with tank covers. I have no way of measuring this scientifically. I do have lots of flow in my tank and the return lines have flared nozzles at the surface, so lots of water movement at the surface. And of course a skimmer, and open sump. The covers are far from airtight, too, with openings for lines, feeding, etc.

I do have a pH probe with my Apex, but so far haven't hooked it up. I do expect pH to fall at night (as a result of more C02), but that happens in every tank from what I understand. What I should do is install my probe and look at my daily pH graphs (Apex monitor), both with the covers on and off, and see if there is a difference.

My fish and corals are all happy, so can't tell from that. I have used covers in the past in my FW days, and again, fish were not affected. I know of no other adverse effects. Only have to clean them every 2 or 3 months, and no salt creep.

The benefits of covers include fish not jumping out, tanks stay warmer longer if there is a power outage, no splashing of water causing salt creep, and less evaporation causing humidity problems. I have Radion LEDs in my tanks (for a couple years now), and they have worked flawlessly, and it may be in part to being more protected from the salt water.

Also, for your interest, here are a couple pics of a 7" sock hangar I made out of a scrap piece of lexan. I like working with lexan, as it is easy to cut and shape/form similar to a thin sheet of metal, but is incredibly strong. Bend a flange wherever you need rigidity. Works perfectly.