Help with plumbing of overflow and return sizes on Waterbox 100.3.

[h4nzo_steel]

I picked up a beautiful tank on Craigslist while searching for parts for my 40g build I was doing. It's Waterbox 100.3, it was only the display tank which I believe is 75 gallons. The problem I'm running into is that it is already drilled and the bulkheads sizes that fit in the 3 existing holes are 3/4" and 1/2". I took the tank to several glass companies to get the holes drilled bigger to fit 1" drains and 3/4" returns, but no one wanted to do it. High risk of cracking the tank.

My question is if that 1/2" return is a big enough size for the pump I'm going to used. I am going with the Varios 4 which had a 3/4" barbed fitting. Will I encounter any problems with the pump being too restricted by the reducing size of the plumbing?

Or can I use one of the 3/4" for the return and use one 3/4" for the main siphon and the 1/2" for the emergency overflow?

Any help is greatly appreciated. I need to get the correct fittings order so I can continue with this build.

Thanks.

 

[mcgyvr]

If it was me in that situation I think I would do a bean animal drain setup using the 2 x 3/4 for the main/partial siphon and the 1/2" for the emergency and doing over the top returns..

 

[h4nzo_steel]

If it was me in that situation I think I would do a bean animal drain setup using the 2 x 3/4 for the main/partial siphon and the 1/2" for the emergency and doing over the top returns..

Yeah. That's what's I was thinking. But that will be the absolute last resort. It's such a beautiful tank, rimless and beveled edges, I don't want to ruin the aesthetics by having a pipe hanging over the back.

 

[mcgyvr]

Then yes.. Set it up as a herbie overflow and see how it works for you..

 

[dkeller_nc]

One thought is actually drilling the back of the tank for the return. That's likely to be considerably lower risk than drilling an already existing hole larger. However, while I've not heard of Starphire glass being tempered, that doesn't mean it's not possible, and a call to Waterbox would be well worth your time if you choose to drill the back for a return.

With respect to return sizes, within reason it doesn't really matter. If the return is smaller than optimal, it means you'll have more head loss than absolutely necessary, and you'll use a bit more electricity than would otherwise be the case.

You can compensate for this with a DC controllable return pump by simply dialing it down and using a slower turnover through the sump. That's advisable for a number of reasons - lower noise, less chance of bubbles getting into the display and less electricity.

Long, long ago when I got into this hobby the recommendation for flow through a sump was really high - in some cases as much as 20 times the tank's volume turned through the sump per hour. Part of the reason for that was that there weren't any such thing as a "propeller pump" for in-tank circulation, so people used drilled-whole, tank-width PVC returns to help with in-tank circulation.

Today, a turnover through the sump as low as 2X the tank volume per hour is not unreasonable if the room the tank's in is kept at a temperature within 10 degrees of the tank's setpoint 24/7.