Is this right?


New member
Ok, while designing the sump/refugium for my new 150 several related questions have arisen and I'm wondering if I've got them right or not. First is line sizing: my drains are for 1.5" bulkheads & my returns are for 3/4" bulkheads, so 1.5" PVC in the input side of the pump & 3/4" PVC on the return side? What if I made the return 1" coming out of the pump?

Next, according to the RC sump calculator you get ~ 1300 gph from a 1.5" drain, so with 2 1.5" drains I'll be flowing ~ 2600 gph through the sump, therefore, in order not to flood my house my main pump (after head loss) needs to be able to pump at least 2600 gph, right? I was looking at the Reeflo Dart as my main pump at 3600 gph at 0 head. So, depending on total head loss then this pump should be sufficient, right?

Since I'm having my sump custom made I need to locate the hole for the bulkhead fitting coming out of the sump at the exact same height as the input side of the Dart so that my PVC is straight into the pump. Anyone know the height of the input side of a Dart so I can locate my sump bulkhead correctly? I'm asking because I'm probably going to have the sump built before I buy the Dart ...

Last question (for now): according to the RC calculator the sump volume needed to handle my tank overflow is ~12.5 gals and the min sum vol for my tank is 39 gals. I assume this number is 'total' including overflow? Also, what is a typical refugium size if your sump is 40 gals and is there any kind of sizing method for refugiums? (My sump & refugium will be physically separate tanks with one part of one of my drains as the input to the fuge and the output from the fuge will be an overflow back into the sump ...)


Active member
just because it has the capacity to drain does not mean it will. Your drains will only drain as much as the input puts in. Does that make sense??? i.e. if your return is 1000gph, then the drains will only have to handle 1000gph - no more, no less. (and DO NOT set it up so that both drains are running maximum - as soon as anything slows them down (algae, snails, crud...etc) you will have a flood...much better to have way more drain capacity than input. I have 2 - 1" and 2 - 2" drains on my 150, using a Dart. it is split into 4 returns - one to the refugium, and 3 to the DT

I use a Dart as my main pump as well - it does not self prime - i orginally had it at the same level as the input from the sump - it would not reliably restart when the power was cut. I have since lowered it about 2 inches - that allows it to be gravity fed from the sump - no more restart issues.

your refugium can be any size you like. I am currently using a 120g tank for my fuge, and a 50g tank for my sump. IMO, it is MUCH better to have way more total capacity in the sump than you think you will ever need. If one of your return lines fails to break siphon when (not if) the power goes out, that extra room in the sump will save you from a flood, dead critters, burned out pump, house fire, etc

also - to answer the first question - there is no benefit to upsizing the return lines from 3/4 to 1" i got a manifold from either or (i think the latter) to handle the return plumbing issue - much easier than trying to make one myself - it was like $7 or so.


New member
In order not to flood your house you cannot excede 2600 gph. The drains will drain up to that much. I'm having my 200 gal. tank equipped with 2-1.5" overflows and plan on running around 1000gph on them in order to get 5x flow through my sump.

Regarding th drain height for your sump, try to find a diagram somewhere, I'm it's out there. Add an inch or so to allow for some padding underneath if you want to have any.

not sure about your other 2 questions


New member
thanks guys. Shortly after posting I realized that those were max numbers so my dart should easily handle my main pump duites. My pump will resting on the floor of my stand so there shouldn't be any restart issues. I planned on making the sump/refugium oversized to deal with the drain back/power out issue but was just curious if there was any methodology to sized a fuge in relation to the sump. I have a RO Ext 300 PS so I need the PS to be able to be in 8-10 inches of water in the sump & still have excess capiticy for drain back ... I'll check out the link on the manifolds as well ...