3/4 in drains for 125?

[Roy 9121]

Why exactly? I'm not saying it might be a good course of action but NEEDS to be?
Would not the pump output regulate the drain size requirement?

Let's say we have a tank with just 2 3/4 lines (for simplicity's sake. We want emergency pipe ect in the real world). The 3/4 drain at full siphon and the 3/4 return has a tee to adjust flow back toward sump (or maybe a controllable flow pump).

Because the return is under pressure, it will move more water. You don't want to let your return overload your drain, that could overflow your tank.

 

[cilyjr]

Because the return is under pressure, it will move more water. You don't want to let your return overload your drain, that could overflow your tank.

Yes but that does not take in to account both a potential siphon on the drain nor pump gph.

If I have a non siphon 3/4 drain and assume it will handle about 300gph. Now let's put a mag 3 pump that pumps 480gph @0 feet on the return let's also assume it's got a head height of 5 feet. The pump returns 270 gph @ 5ft. That means there's 30gph leeway here regardless of return plumbing size. These are all estimates so don't take this math as fact but it does illustrate my point.

 

[Roy 9121]

Yes but that does not take in to account both a potential siphon on the drain nor pump gph.

If I have a non siphon 3/4 drain and assume it will handle about 300gph. Now let's put a mag 3 pump that pumps 480gph @0 feet on the return let's also assume it's got a head height of 5 feet. The pump returns 270 gph @ 5ft. That means there's 30gph leeway here regardless of return plumbing size. These are all estimates so don't take this math as fact but it does illustrate my point.

That's why i asked whether it was a siphon or a gravity drain system. I would still want my drain line larger even if it's a siphon, but it's up to you. And i wouldn't throttle back my pump, since it should have been sized for your tank.

 

[cilyjr]

I'm not saying any of this is a good nor bad idea but anything is possible if done right. That aside the above scenerio is applicable with a simple durso drain. Though would require careful planing

There are ways to throttle back a pump without damaging it.
1. Is buy a dc pump as they are controllable
2. A tee returning a portion of pumped water to the sump will work for any noncontrollable pumps

 

[Roy 9121]

I'm not saying any of this is a good nor bad idea but anything is possible if done right. That aside the above scenerio is applicable with a simple durso drain. Though would require careful planing

There are ways to throttle back a pump without damaging it.
1. Is buy a dc pump as they are controllable
2. A tee returning a portion of pumped water to the sump will work for any noncontrollable pumps

I didnt say you would damage the pump. But if your tank needs 300 GPH flow, and you bought a 300gph pump, you don't want tho restrict the flow of the pump because then you won't have the 300gph your tank needs.

 

[coralosity351]

I bought the bit i need and the tank now has a bean animal overflow with 1 inch drains

 

[gobble]

Old thread but I have a question related to it.

I’m running a Herbie system in a new Innovative Marine 25 gallon EXT tank. The bulkhead is 1” but I’m running a 3/4” line because the largest gate valve I could find locally was 3/4”.

Even though both return lines are 3/4”, the fully opened hole in the gate valve seems to be significantly smaller then 3/4”. Is it fair to quote a flow rate for a 3”4” line when the valve on that line is more restrictive?

Regardless, I’m thinking I don’t need to jump to 1” for a 25 gallon tank? I’m curious to hear thoughts.