Overflow question

[USMA36]

I have 2 stockman standpipes in my overflow. I would like to cover the overflow box to keep critters and algae out. How tall should the standpipes be? Right now they stick up a little and I can't properly cover the overflow box. Safe to trim the standpipes down? I don't want the. Too low that my sump floods should my return pump fail. See pictures below. You'll see how the cover sits in the second picture.

 

[Smo]

Have you considered converting to a Herbie drain system?

 

[USMA36]

No I have not. Tank came with these and if possible I'd like to give it a try, I would really like to cover my overflow though. If there is no other solution than I will dry different overflow methods.

 

[AZDesertRat]

Since that overflow box has slots near the bottom that also allow water in, the level in the tank with siphon down to the level of the standpipes when power is off. If you had a normal internal overflow with just slots/teeth on top the tank would only siphon down to the bottom of the teeth on top of the box or to your return nozzle, whichever is lower.
If you have sufficient room in your sump to safely contain several more gallons of water you could shorten the standpipes the extra inch or so you need, otherwise I wouldn't attempt it.
It is easy to calculate how much water is contained in an inch of your display, LxWxH(in this case 1" or whatever you determine you need)/231. In my 60"x18" 100 gallon tank 3/4" equals 3.5 gallons and 3/4" is how far it drops when power goes off. My sump is a 30G that normally runs about 2/3 full so there is plenty of room to safely contain the extra 3.5 gallons. You will need to do a little math or experimenting until you feel comfortable.

BTW, I have used a single Stockman standpipe for 14 years on my current system and on others before that and never once had a single incident. I even push it to the max with a Water lasted HY-5000 pump running wide open.

 

[Fudsey]

That overflow has 2 walls, the slotted one and a fully closed one that is shorter. You can see it in the 1st pic. I had the same overflow on my 72bf. He should be able to lower the stand pipes because of it

 

[USMA36]

Yes it is a double walled overflow box so the water won't be coming in from the bottom. I ended up cutting 1/2" off each standpipe so the cover fits well now. Hopefully it won't cause any waterfall problems or anything like that. I'll know soon enough. Tank is about 1/2 full so far. Waiting for ro/di unit to make me some more water.

 

[Not_Eeyore]

Someone else was looking for a double walled overflow...any idea what brand that is?

I would get a hole drill bit and make holes for the pipes to stick out, then get a couple of black caps to attach over the pipes.