Do I need to fish/snail proof my bulkheads?

[ReefsandGeeks]

I'm working on setting up a new tank but it's different than tanks I've had before, so lots of questions comming up. Up untill now, I've never had a sump. all of my tanks have used either HOB filtration, or canister filters. The new tank I'm working on is a 150 gallon with 2 bulkheads near the top on one side which will drain down to the wet/dry sump. I'm just now starting to think that having these bulkheads is goign to invite my fish or snails to get sucked into the sump, and since it's a wet/dry, they would get stuck on the filter floss pad and likely not found very quickly.

What's the best way to prevent any fish or snails from getting sucked into the bulkhead overflows? The bulkheads are just connected to holes drilledi n the glass. I don't have those black columns with the weirs on top on my tank. Would I need to make one and somehow glue it to my tank? I was reading about silicone not sticking very well to acrylic, so I'm not sure I could make an overflow box for it and silicone it in place since silicone won't stick? Any thoughts?

[Vinny Kreyling]

https://www.bulkreefsupply.com/bulkhead-overflow-strainers.html
Unless it's going to be fish only a wet dry filter is NOT recommended.
Live rock does the filtering.

[ReefsandGeeks]

Ahh, those will be much simpler than an overflow box. A cleaner look IMO too. Thanks!

Yeah, I was planning on putting plenty of LR rubble in the sump as well, along with the skimmer and usual filtration equipment. I've been back and forth on whether I wanted to try leaving the bioballs in there for now, or take them out. If I take them out, I don't know if I'd be able to utalize that space for anything or not since there's no standing water in that, or any, chamber in the sump. The water level will only be about 6 " or so across the whole sump. I'd rather make that chamber all LR, but without it being submerged I don't think that will work. I can't block it off because then there'd be alot less empty space in my sump to handle the overflow when the return pump shuts off. So for now I feel stuck

https://www.aquacave.com/eshopps-wd-150-cs-wet-dry-filter-sump.html?fee=1&fep=5270&gclid=CjwKCAjwu5veBRBBEiwAFTqDwaL7CUHEv18ZB9hbyeIlLnirY5yJY6vQVVXuxav4jem32gUEqE8OqRoCVd0QAvD_BwE

That's the sump I have currently. Wouldn't have been my first choice, but it came with the tank so I'm going to try to make due with it for now until I can buy/build a better more normal sump.

[Vinny Kreyling]

It's just a box. As long as it does not overflow you can raise the water level.

[ReefsandGeeks]

right. I guess I'll have to wait untill I have my tank up and running so I can see how much water pours out of the display and into the sump during a power outage, then can possibly raise the water level in the sump if there's extra wiggle room there. I don't know if there's a good way of estimating how much the tank water will fall when the return pump shuts off. Depends on the return pump flowrate and how well the bulkheads/overflow work.

[Vinny Kreyling]

Best way is to keep the return lines high in the water so not much siphons back.
You can always drill a hole on the return pipe just below the surface facing downward too.
Start out with the sump about 1/2 full, add water only if pump will run dry.
After all is running smoothly shut down to check water level.
Space above that level is what you can increase running level to minus a safety area.

[ReefsandGeeks]

Great advice, I will absolutely do that. Thanks! I didn't even think about the water siphoning back the return line. I was only thinking about the extra water level in the display that would naturally drain out the bulkheads until the level hit the bottom of the bulkhead.

[ReefsandGeeks]

I'm in process of filling up my display now and am wondering what additional safety measures I can take to prevent back siphoning through my return line. I do plan to keep the outlet not far below the water surface level, and also drill a small hole just below the surface level to act as a back up to break the siphon if needed. Would it be worth adding a check valve to the return line as well? If so, what's a good option? I have a Mag 9.5 and currently have .75" flexible return line. May eventually switch to hard plumbed PVC, but at least not until I play around with the return and know I'm happy with the flow in the tank.

[Vinny Kreyling]

Check Valves are a disaster just waiting for the right time.
Make the siphon hole 1/4", not smaller & check to make sure it does not get clogged & you should be good to go.

[ReefsandGeeks]

Fair enough. I may get a check valve soon to install as a back up safety measure, but will for sure rely in the hole to break the siphon as the primary way of preventing back flow into the sump.