Bought a used tank...help!

sberto

Member
Hey there salt water friends.

Well. I bought a "new" tank that I pickup tomorrow. 90g with the corner overflow. I've been reading a lot about sumps and hear that the herbie style overflow is the way to go. However this one I bought doesn't have it. I'm wondering if I can convert? Any thoughts? The pic is the overflow. I pickup tomorrow so I'm kinda nervous on what to do with this.
 

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silverado61

Well-Known Member
It looks like with the herbie, the tank has to be drilled in the floor. Most floors are tempered and cannot be drilled. The floor will shatter into thousands of tiny little pieces.
 

silverado61

Well-Known Member
You could always drill the upper back wall for over flows. Then run plumbing to the sump. You only get one chance at that though.
 

lmforbis

Well-Known Member
Looks like a standard marine land corner overflow. It will have two holes drilled in the bottom. One as a drain and one for the return. They work well. Mine is a dual overflow but essentially the same.
 

sberto

Member
2quills can you explain a little more on your external return please?

And Imforbis, I was concerned about noise in the tank and overflowing the sump etc. Any concerns with that on yours?
 

lmforbis

Well-Known Member
You need a sump big enough to hold any water that flows down if the return pump is off. The sump isn't supposed to be full. The tank only drains about 2 inches so you need that much empty volume in your sump. My tank is 120 gallons. I have a 40 gallon sump. It is only about half full. When the power is off to the return pump the sump fills but there is still a couple inches between the max water line and the top of the sump. My sump is in the basement under the tank so I have a lot f plumbing to it. The tank isn't loud at all. I have the dual over flows. They are meant to be two drains and to returns. I use both drains and one return. The other return I use as an emergency drain. It it's above the water line and below the rim of the tank. An external return would simply go behind the tank and over the edge instead of through the bottom. Super easy to do with a bit of PVC.
 

2quills

Well-Known Member
2quills can you explain a little more on your external return please?
It just means running the return line from your pump on the outside of the tank, up and over the top.

Then you can use the small hole on the tank itself for your siphon drain and the larger hole for the open channel drain.

I run a dual Herbie set up on my tank and it is significantly quieter than traditional open channel drains IMO.

.02
 

sberto

Member
Well I'll have to take a look tomorrow and see how it all looks. The reviews on the herbie style seem to be really good. And running the external return wouldn't be tough at all. Some pipe, a valve and good to go.

However, because on the bulkhead there is an opening half way down, do I need to block that off as well? If the power went, wouldn't water drain to that point? Or am I just confusing things.
 

2quills

Well-Known Member
If you're referring to the overflow cover with the slits you don't necessarily need to cover it.

If you don't the water level in the tank will drop to the until it reaches the opening on the siphon drain at which point it will start sucking in air and break the siphon. Same principle goes for your return line, keep it up near the top of the tank.

However, if you were to block those slits on the lower portion of the cover then the water level will only drop to the bottom of the siphon drain inside of the overflow itself so it would be less the sump would have to handle.

And as mentioned the opening on the return line's output is the only other factor to consider. Which ever opening is the deepest inside of the tank be it the return or the drains will dictate how much water backflows into the sump when power goes off.

Water in my tank drops about an inch with the way mine are set. 120g tank, 65g sump. I have plenty of wiggle room.
 

sberto

Member
And what would be recommended to block those slits on the bottom portion? What's the purpose of them anyways?
 

2quills

Well-Known Member
If the slits don't go all the way through then it shouldn't matter if u cover them. I think the intent was to collect particulate matter lower in the water column.

You're looking at 3.75 gallons of water for every inch the water level drops in the 90g tank. I personally would shoot for a maximum 3" drop, or 11-12 gallons or less if possible. Make sure the sump can handle the extra.
 

sberto

Member
I wonder what the point of the lower slats are then? So water comes in, directed upwards and into the over flow box?

I'd still need to cover them would I not ?
 

sberto

Member
Couldn't pickup the tank today...hopefully within the next few days. Ill keep you guys posted and let you know when (and there will be a when) I have questions!
 

sberto

Member
Alright. I picked everything up today. Set it up at my place...threw my back out

But. On the bright side. Everything is running. Sorta. I've attached a picture of the sump as he had it. One of the compartments is more sant and rock. Can I take that out and turn it into a refugium?

Also right now it sounds like a constant running water. I take it that goes away in time?
 

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