2 aquariums, 1 sump?

RobinC · Jan 28, 2023

Looking for some suggestions. I have a 125g 6 foot long tank. It has a 90g sump... I would like to add a 29g planted tank for raising cardinals in the future. I want to put this beside the first tank, and plumb it into the same sump. I cannot however think of how to flood proof the 2nd tank.
So, overflow from 2nd tank into same sump, and either split the return pump to feed both tanks, or add a second smaller pump for 2nd tank. However, if 2nd tank loses siphon (It isn't drilled), the pump wouldn't run out of water, and keep feeding the tank until, well you know....lol.
Also, to note....The room is rather small, so the tanks would be beside each other, but at 90 degrees. One on one wall, and the 2nd beside it on another wall.
I really like the idea of having a planted tank on the same system as my big tank for obvious benefits. More volume, more plants, etc.
I guess I could bite the bullet and just get a reef-ready, but was hoping to work with what I have.
Thank you in advance.

Larry Stewart · Jan 28, 2023

Hi Robin....maybe on a closed loop set up. However, I'm thinking that the 29 gallon tank should probably be drilled to prevent issues. Just a thought. (My two pennies)

**** Or just section off. Portion off your 90 gallon sump to create/build a planted section. A 90 gallon sump seems like a lot of space to be creative.

- Larry

chipmunkofdoom2 · Jan 28, 2023

I have this kind of setup with a 40 gallon breeder and a frag tank. The breeder isn't drilled and uses a HOB overflow box.

The thing that nobody talks about with HOB overflow boxes is you need to have a decent amount of flow moving through them to keep the siphon. You can't have a 1200 GPH HOB overflow and only run 200GPH through it. If you only have a trickle running through the box, then bubbles form and build up in the tube, eventually breaking the siphon. If you have enough flow moving through the tube, the bubbles get swept through. No bubble build up, no siphon break.

With adjustable return pumps, this is pretty easy these days. Just increase or decrease flow until you don't see any bubbles building up after a few days. Alternatively, if your return feeds both tanks, add a ball valve and adjust flow to the HOB overflow tank until there are no bubbles built up after a few days.

Clarkjw2002 · Jan 28, 2023

I'll have a similar set up on my retirement build. 125 HOB plumbed to the sump of a 300gal display. I have a life reef double overflow box rated at 1200 gph I think. I plan to only run 4-500 through it and set up the overflow Herbie style (so one pipe is full siphon while the other is an emergency drain).

Never had a problem with air bubbles in the past when I ran two life reef overflows on this tank but was probably pushing 800gph or so.

Hadn't really thought about overflow proofing the second tank so maybe I'm too trusting of the life reef overflow. But I'll be home all the time too so can check on the tubes everyday between farm chores.

ryanjohn1 · Jan 28, 2023

RobinC said:
Looking for some suggestions. I have a 125g 6 foot long tank. It has a 90g sump... I would like to add a 29g planted tank for raising cardinals in the future. I want to put this beside the first tank, and plumb it into the same sump. I cannot however think of how to flood proof the 2nd tank.
So, overflow from 2nd tank into same sump, and either split the return pump to feed both tanks, or add a second smaller pump for 2nd tank. However, if 2nd tank loses siphon (It isn't drilled), the pump wouldn't run out of water, and keep feeding the tank until, well you know....lol.
Also, to note....The room is rather small, so the tanks would be beside each other, but at 90 degrees. One on one wall, and the 2nd beside it on another wall.
I really like the idea of having a planted tank on the same system as my big tank for obvious benefits. More volume, more plants, etc.
I guess I could bite the bullet and just get a reef-ready, but was hoping to work with what I have.
Thank you in advance.

Crp cs50 external overflow. Has small lift pump. I have one works great

Fish Styx · Feb 21, 2023

I do this exact same thing on my system. My advice: 1) drill the second tank for an overflow; 2) plumb it off your return via manifold; and 3) do not plumb the 2nd tank's drain into the same section as the main drains from your DT-- it will cause your 2nd tank to overflow (trust me on this). Instead, drain it into the refugium section of your sump. Be sure to post pics of what you come up with. Happy reefing!

Enderg60 · Feb 21, 2023

Its no problem at all. I would recommend separate pumps for each tank though.

My current build is a 330g display with a 320g frag tank all on one sump.

The only downside is if you get a pest or illness its in both tanks not just one. But not having to dose or maintain things twice is a big plus.

RobinC · Mar 15, 2023

Fish Styx said:
I do this exact same thing on my system. My advice: 1) drill the second tank for an overflow; 2) plumb it off your return via manifold; and 3) do not plumb the 2nd tank's drain into the same section as the main drains from your DT-- it will cause your 2nd tank to overflow (trust me on this). Instead, drain it into the refugium section of your sump. Be sure to post pics of what you come up with. Happy reefing!

Purchased an eshopps M...a Nauitilus 3200, and ended up with a good deal on 2 40g breeder tanks and stand. We only have to drill 1 hole, so hoping the first attempt works. If not, have a second tank to try, lol. Just picked up the 40's today, and awaiting the rest to arrive. Hopefully a busy weekend, if all arrives on time.

RobinC · Apr 3, 2023

RobinC said:
Purchased an eshopps M...a Nauitilus 3200, and ended up with a good deal on 2 40g breeder tanks and stand. We only have to drill 1 hole, so hoping the first attempt works. If not, have a second tank to try, lol. Just picked up the 40's today, and awaiting the rest to arrive. Hopefully a busy weekend, if all arrives on time.

twentyleagues · Apr 3, 2023

Nice. Looks like it's working. I was worried when I read you were looking to use a hob. Those all eventually fail.

C4ctus99 · Apr 3, 2023

I’ve got a 75 gallon tank, cannot drill the bottom cause I know it is tempered and it’s Aqueon and right now they say they are using tempered glass on random panels due to a shortage of regular glass. I found designs for a self restarting siphon online so I’m going to try and mess around with, We’ll see whether or not it works

Rmckoy · Apr 3, 2023

I’ve considered the same idea .
but the way I see it I would have to add a overflow to the new tank , and a separate return pump .
depending on the water depth in the sump if it can handle the amount of water from the added tank if the power were to be disconnected .
Lowering the water level in the return pump section of the sump could help

twentyleagues · Apr 3, 2023

C4ctus99 said:
I’ve got a 75 gallon tank, cannot drill the bottom cause I know it is tempered and it’s Aqueon and right now they say they are using tempered glass on random panels due to a shortage of regular glass. I found designs for a self restarting siphon online so I’m going to try and mess around with, We’ll see whether or not it works

I found that out the hard way

.Weirdest thing was the front and back panels were not tempered the bottom was, I didnt even check the sides. Guess what was tempered and where i wanted to drill. All I can say is its not tempered any more.

o2manyfish · Apr 3, 2023

Drill the tank!

This makes it a pretty brainless system. For the planted tank you don't need much flow, so just run a T off of your return line with a small gate valve and you will be fine.

I have 4 tanks plumbed into 1 sump - 750g, (2) 180g & 100g into a 270g sump. There are no overflow issues and the system has been up and running for many years.

Key is to drill the tank and remove an item that you know has the potential to cause issues.

Dave B

RobinC · Apr 3, 2023

Rmckoy said:
I’ve considered the same idea .
but the way I see it I would have to add a overflow to the new tank , and a separate return pump .
depending on the water depth in the sump if it can handle the amount of water from the added tank if the power were to be disconnected .
Lowering the water level in the return pump section of the sump could help

New pump has a feed mode, shuts off for 10, 30, or 50 mins. We tested the water level multiple times with pump off. And I use the feed mode twice a day for feeding now. 5 inches to spare in sump.

RobinC · Apr 3, 2023

Since I plan on using the planted tank for future breeding of my clowns & cardinals, I set the over-flow pretty high in the tank. Lowering water level an inch and a half, and using sponge filters= instant breeding tank. Valves below the drain, and off the return to this tank can be closed. I still have a 10g, 29g for qt/med, and another 40g breeder for baby rearing. The Eshopp's eclipse took forever to get here, so I had almost 2 weeks to plan, and drive hubby nutz with changes, lol.

Rmckoy · Apr 3, 2023

RobinC said:
New pump has a feed mode, shuts off for 10, 30, or 50 mins. We tested the water level multiple times with pump off. And I use the feed mode twice a day for feeding now. 5 inches to spare in sump.

5” is more than enough. .
When I turn the power off for my dt .
i have maybe 1.5-2” at the top of my sump

maybe time to upgrade the sump soon