Return plumbing Nem Tank/No powerheads

[Kristophf]

Hi i have a 2.5x2.5x2ft (about 350L) almost cube made with an overflow box built into the back. The 3 drain pipes are 1". There are 2 holes for return, 1 at bottom left and 1 at the top right. I got a maxspect turbine 9k pump for return and plan to use this to create flow and avoid wavemakers. I was initially going to use 3/4" to return but found 1" bulkheads fitted perfectly so im now considering plumbing the return in 1". I was also thinking of finding loc line with random flow generator heads.

Should i stick with 3/4" pvc for return if would 1" be better for flow?

Any thoughts would be appreciated

 

[Robert_ellis]

Bigger is better. Put a ball valve on the feed lines and you can adjust down. Cant really adjust up without redoing the plumbing.

 

[Kristophf]

Bigger is better. Put a ball valve on the feed lines and you can adjust down. Cant really adjust up without redoing the plumbing.

Yea i thought so. The return line will be one line with a T, the turbine is controllable i think ao i can adjust speed but i didnt think a ball valve would be good for the pump

 

[laverda]

I would think real carefully before using the lower return. In a power outage the water will drain to that point unless you do some creative plumbing. I would never trust a one way valve for that. The risk is way to high. My quests is it was used as a drain for water changes not as a return line. One 3/4” return is plenty since your drains are only 1”
If it was me I would plumb in a 1” SCWD in your return mounted high enough you eliminate the syphon risk. Feed each output to one of your returns. This will give you changing flow between the 2 returns. Set up the SCWD so it can be removed and cleaned easily. I have plumbed several smaller tanks this way. I modified the 3/4” SCWDs to fit in the return pump compartment on 2 JBJ nano cubes and on my 29 gallon Cardiff. It worked really well on the Cardiff with the front curved glass. One return was in the standard location in the upper Rt rear of the tank. The other was probably 4-5” above my sandbed on the opposite lt rear of the tank similar to how your returns are. If you look closely at my avatar photo you can see the lower return between the two upper legs of the red linka starfish.
Since your drains are 1”, 3/4” should be plenty for the returns. Run 1” to the SCWD the 3/4” to the tank return lines.

 

[Kristophf]

I would think real carefully before using the lower return. In a power outage the water will drain to that point unless you do some creative plumbing. I would never trust a one way valve for that. The risk is way to high. My quests is it was used as a drain for water changes not as a return line. One 3/4” return is plenty since your drains are only 1”
If it was me I would plumb in a 1” SCWD in your return mounted high enough you eliminate the syphon risk. Feed each output to one of your returns. This will give you changing flow between the 2 returns. Set up the SCWD so it can be removed and cleaned easily. I have plumbed several smaller tanks this way. I modified the 3/4” SCWDs to fit in the return pump compartment on 2 JBJ nano cubes and on my 29 gallon Cardiff. It worked really well on the Cardiff with the front curved glass. One return was in the standard location in the upper Rt rear of the tank. The other was probably 4-5” above my sandbed on the opposite lt rear of the tank similar to how your returns are. If you look closely at my avatar photo you can see the lower return between the two upper legs of the red linka starfish.
Since your drains are 1”, 3/4” should be plenty for the returns. Run 1” to the SCWD the 3/4” to the tank return lines.

Thank you. I have 2 safety valves i was going to place below each return. Are they not reliable enough? And so are you saying to go 1" from the return to the SCWD and then T off 3/4" after? Im in australia and parts like that might be hard to find but ill have a look

 

[Kristophf]

Also for backup i have a UPS that will grant me a few hours in a power outage

 

[laverda]

Thank you. I have 2 safety valves i was going to place below each return. Are they not reliable enough?

That is up to you to decide. It only takes a little bit of growth or sand to stop them from sealing. If you go that route make sure you can remove clean them easily.

And so are you saying to go 1" from the return to the SCWD and then T off 3/4" after? Im in australia and parts like that might be hard to find but ill have a look

Exactly, not that it is critical. I believe Marine Depot will ship there. If not and you can not find one locally let me know.