sump baffle sizing

[fermentedhiker]

Getting ready to cut some baffles for a 40L sump. I'm just curious how much smaller than the inside width of the tank to you usually cut them for proper fit. Since my 40L is 12.5 inches wide on the outside with 1/4" glass, the inside dimension is 12". A perfectly sized cut wouldn't allow room for silicone and would be pretty impossible to actually get in place. How much is a normal reduction 1/8" or 1/4"?

Thank for the help.

 

[TaylorPilot]

Glass or acrylic?

 

[fermentedhiker]

Sorry should've included that. Glass. Just a standard glass 40 long

 

[TaylorPilot]

I would cut them 1/4" short over all, so there is a 1/8" gap on either side. If it had been acrylic, I would make it a little more.

 

[mcarroll]

I would skip baffles and leave the sump open.

IMO, there are a few specific cases where they can be useful, but in general they take up space, don't work as expected and mostly just limit what you can do with your sump in the future.

I made a bubble stopper from PVC parts that rests on the bottom of the sump under its own weight...my ATO sensor is zip-tied to that. Otherwise my sump is wide open for my skimmer and heaters (etc) to be where I want.

$0.02

 

[TaylorPilot]

I would skip baffles and leave the sump open.

IMO, there are a few specific cases where they can be useful, but in general they take up space, don't work as expected and mostly just limit what you can do with your sump in the future.

I made a bubble stopper from PVC parts that rests on the bottom of the sump under its own weight...my ATO sensor is zip-tied to that. Otherwise my sump is wide open for my skimmer and heaters (etc) to be where I want.

$0.02

I can concur with some of that. I once had a 40b as a sump and had no baffles at all, just used an ato as my level for the skimmer. Only difference would be if you were running a multi drain system (herbie or bean animal) and want to run filter socks. Drop in sock holders are nice.

 

[fermentedhiker]

I'm not using many, just three. The first is a must to keep the water level high enough to cover the heaters if the ATO breaks and I'm away for long enough for evap to b detrimental. Half the sump will be open.

 

[mcarroll]

I can concur with some of that. I once had a 40b as a sump and had no baffles at all, just used an ato as my level for the skimmer. Only difference would be if you were running a multi drain system (herbie or bean animal) and want to run filter socks. Drop in sock holders are nice.

Right on! And with an open sump, you have the option to place those sock holders anywhere....and move em if you want! Or decide they're a pain and take em out! Or only use them as needed....during maintenance, etc...and have them out of the way in a closet day-to-day.

I'm sure there are use-cases I'm not thinking of, but off-hand, the only reason I can think of for gluing a panel into a sump is if you need a permanent separate compartment for something like a refugium. There are usually critters/plants there that you don't want migrating to your ATO sensor and return pump, plus you may want deeper water. I control nutrients the old fashioned way - through low stocking levels - so I have more use for an open sump than a refugium.

 

[mcarroll]

I'm not using many, just three. The first is a must to keep the water level high enough to cover the heaters if the ATO breaks and I'm away for long enough for evap to b detrimental. Half the sump will be open.

I hesitate to ask, but how big/small is your sump and how long are you typically gone on trips for that to be a concern? Makes me think you have a sump with 2-3" of water running in it.

I have a 30 Long as a sump and it runs just under half-full. If the ATO were to fail, it would take several days - maybe even a week or two - for pumps to be exposed...and at least a few more days for the heaters to become exposed.

Setting that wall only makes that window of time all the much shorter before your return pump is toasted in that same scenario. Only instead of weeks it'll be able to happen in days since the return chamber will be tiny.

A 40B is 36" x 18".

An inch of water in that space is about (36 x 18 x 1 = 648 cu in / 231 =) 2.8 gallons.

If you wall that off to only 10" x 18" (a typical return chamber space), you would only have to evaporate just over 3/4 of a gallon to drop the same 1". You have only a quarter the amount of time to find the failure before something bad happens.

Even if you literally only wall half the sump off, that's still literally half the amount of "safety time" you have allotted to your situation. If you really really want to have walls in your sump, it would make more sense to have a tiny heater/drain water chamber and to leave the majority of space to be controlled by the ATO sensor. Personally I don't even think that makes much sense though, given the bother and space-reduction in the rest of the sump.

Open-sump is definitely the way to go for safety and flexibility, IMO. I've had ATO's fail on as well as off in this model and never had an issues, BTW....but I'm not away for excessively long periods either.