New tank design graphic ... Tell me what you think...

[Myka]

Originally Posted by Megalodon

That is correct. The backup overflow is higher than the other two. The backup drain line also doesn't have a gate valve and it's completely unrestricted.

In your drawing it looks like all your bulkheads are the same height. How are you going to get your backup overflow higher than the primary overflows without having to keep your entire tank water level much lower than the rim of the tank? You need to have quite a height difference between the backup drain and primary drain(s).

[Megalodon]

Originally Posted by Myka

In your drawing it looks like all your bulkheads are the same height. How are you going to get your backup overflow higher than the primary overflows without having to keep your entire tank water level much lower than the rim of the tank? You need to have quite a height difference between the backup drain and primary drain(s).

No, the backup overflow is higher. Regardless, I've decided to heed your advice, as the way I was going to do it would require a larger sump to take up access water in the event of a power outage.

Check out my next revision. Tell me if my overflow box sizes look OK in relation to the tank size.

[Megalodon]

OK, this will probably be my final revision...

I've added Herbie overflows and a larger refuge.

A - 3/4" overtop PVC return manifold
B - 1" bulkhead and strainer leading to external overflow box
C - 1" Herbie backup overflow drain
D - 1" Herbie drain and strainer
E - External glass overflow box
F - 1" Spaflex backup drain pipe (left)
G - 1" Spaflex drain pipe
H - 3/4" Spaflex return pipe
I - 1" Spalfex drain pipe (right)
J - 1" Spaflex backup drain pipe (right)
K - ½"gate valve teed off from return
L - ½" Spaflex refuge feed from return
M - 20-gallon glass refuge
N - refuge light
O - 1" drilled bulkhead/refuge overflow
P - 3/4" Spaflex refuge drain
Q - 3/4" Spalfex refuge backup drain
R - 20-gallon glass sump w/ large return area
S - Baffles more than 1" apart
T - Eheim 1262 return pump
U - AquaC EV-180 protein skimmer
V - Drain area with filter sock

* White pipes are dirty tank drain water

* Grey pipes are clean return water

* Pink pipes are backup only and won’t usually have water in them

[mark]

Not sure of any formula for the size of overflow box other than on RC's (here) where they mention linear weir length.

Picture is of Skimmin's set up. (clearer picture here). Those boxes were handling ~1000gph each.

[Myka]

Ya, I'm not sure on the overflow box size either. I haven't got that far in my plans.

I don't think you'll be able to regulate the flow well enough on your drains without putting a separate gate valve on each one. Now, I'm just wondering here, but is there a reason you aren't drilling your returns?

[Megalodon]

Originally Posted by Myka

Ya, I'm not sure on the overflow box size either. I haven't got that far in my plans.

I've decided to make them 17cm long, 20cm deep, and 10cm wide.

Originally Posted by Myka

I don't think you'll be able to regulate the flow well enough on your drains without putting a separate gate valve on each one. Now, I'm just wondering here, but is there a reason you aren't drilling your returns?

I'm going to do that now too. See my next diagram. (Yes, sorry, another one, LOL.)

I'm not drilling the returns because I'm not sure if the sump will be big enough to take up the access tank water during a power failure.

[Myka]

Originally Posted by Megalodon

I'm not drilling the returns because I'm not sure if the sump will be big enough to take up the access tank water during a power failure.

Gotcha!