What's the Best way to prevent H2O overflow during power outage?

[tbone28]

<a href=showthread.php?s=&postid=9644565#post9644565 target=_blank>Originally posted</a> by CSS Reef
What are you using to return from your main pump back in to your tank?If you use locline fittings then you can just adjust the output as high or low as you want. I know some think they are ugly but I like the adjustability. Also, I would think it depends what return pump you are using as well. If your outflow is above the water line on a really strong pump you might get too much open jet flow, splashing and chance of introducing some microbubbles?? Personally I wouls just use the locline and and you can adjust to the capacity of your sump.

I'm in the planning stages right now - haven't decided on a pump yet. I'm trying to set it up right the 2nd time around, so I avoid the issues I had on my 240g. I had 2 of the Velocity T4's as returns on my old tank. Not sure if I want to go that route again.

Seems like the 2 biggest factors right now (in regards to overflow) are sump size, and the way I plumb the tank. I was thinking a 75g sump. That should be big enough?

 

[techigirl78]

Here, try this calculator: http://www.reefcentral.com/calc/sump.php

Then draw up your sump design and measure (l, w, h) the area in the sump that will be empty (given the location of your auto top off and baffles). Then, use the following calculator to make sure it is large enough: http://www.reefcentral.com/calc/vol.php

Using this method has worked a few times for me with no problems.

 

[tbone28]

Thanks everyone for your help!

Techgirl, I checked out your link, and that is very helpful!

So let's say, worst case scenario, my overflow teeth are 2" and I submerge my return lines, but place them no lower than 2" below the water surface.

If the power goes out, I'll drain this much H2O on a 6'x2'x2' tank:

72x24x2 / 231 = 14.96 gallons

I plan on buying the EuroReef RS250 in-sump skimmer, which holds 3.69 gallon.

So, my sump needs to be able to hold about 19 gallons during an outage.

If I use an old 90T (48x18x24) acrylic tank as a sump, and have the water line about 2/3 the way up, I'll have an empty space of 48x18x8, or about 30 gallons, so I should be safe from overflows during an outage.

Am I doing this correctly?

 

[AZDesertRat]

Two things, keep the returns close to the surface and maintain room in the sump for a worst case backsiphonage. Check valves and drilled siphon holes are 5.6 gallons back into the sump so I always keep about 8 gallons available above my high water level in the sump.
You are doing it correctly.

 

[cbeitel]

IMO every system should be bullet proof when it comes to overflow. Floods should never happen due to a power outage.

I put 2 overflows (2 drains/2 returns) in my 140 and have 15g of overflow space in my sump.

So, I think you are on the right track with a bigger sump. Your calculations look right!

 

[sjm817]

With a 180, you have plenty of room for a large sump. It should not be a problem.

Design the system so that the sump will hold all the water that back siphons.
-Use a large sump
-Dont build the baffles in the sump too high. Leave plenty of reserve room
-Dont put your return lines far underneath the waterline. Just below will typically drain the tank just below the over flow weir line.

 

[tbone28]

<a href=showthread.php?s=&postid=9649448#post9649448 target=_blank>Originally posted</a> by sjm817
With a 180, you have plenty of room for a large sump. It should not be a problem.

Design the system so that the sump will hold all the water that back siphons.
-Use a large sump
-Dont build the baffles in the sump too high. Leave plenty of reserve room
-Dont put your return lines far underneath the waterline. Just below will typically drain the tank just below the over flow weir line.

In regards to the baffles, what is the general rule of thumb on baffle height? How high is too high?

edit: I just noticed your sig - your setup is very similar to what I plan on doing: AGA 180g, T5's, with a couple of Tunze's

Do you need to run a chiller with your T5's?

 

[sjm817]

No chiller. I'm fundamentally opposed to using electricity to heat the water with lights, then use more to remove it again with a chiller. My 75G sump is in the basement and there is also a 30G fuge. Baffle height depends on the purpose/layout of the sump and skimmer. Mine are 12" high. When the power is off, the level in the sump is ~ 15" which leaves ~ 20G of "air" space when the power is off.

 

[tbone28]

No chiller - great news. That's what I'm shooting for. I'm coming off a 240g Reef, with 4x250w halides and 4x65W actinics. I am trying to minimize the electricity used and need for a chiller this time around

 

[sjm817]

What is your plan for the T5s?

 

[tbone28]

I've been following the T5 thread, and am waiting for ReefGeek to carry the ATI's. I haven't decided between the Powermodule and SUnpower yet. My T5's will be going behind cabinetry, so the Sunpowers seem to be the way to go due to the price (half!). However, I don't plan on running a chiller, so I like the fact that the Powermodule has more fans. I think it has 1 fan for every 2 bulbs, whereas the Sunpower has 1 fan for the entire fixture.

I plan on a mixed-reef, but with a majority of SPS. On a 72" tank, I'd need to run 36" fixtures.

The Powermodule has 8 and 10-bulb fixture. I could run 2x8-bulb or 2x10-bulb fixtures over the tank. This makes for an easy setup.

With the Sunpower, however, they only come in 4-bulb and 6-bulb setups. If I run 2x6-bulb, I don't think that will be enough light 12x39w=468w. So, I was thinking if I go with the Sunpower, I'd need to hang 4 fixtures over the tank!! Either 2x4-bulb plus 2x6-bulb or 4x4-bulb. This is the cheaper way to go, and i could mount an external fan to make up for the fewer built-in fans. I'm just not sure about hanging 4 fixtures above the tank.

I'm also considering the Aquactinics Constellation (14x39w) in a 72" fixture, but am concerned that it's only 14" wide.

 

[sjm817]

I run (6) 60" bulbs with IC reflectors and 660 ballast over my 180. You dont notice the 6" gap on the ends.

 

[tbone28]

<a href=showthread.php?s=&postid=9653153#post9653153 target=_blank>Originally posted</a> by sjm817
I run (6) 60" bulbs with IC reflectors and 660 ballast over my 180. You dont notice the 6" gap on the ends.

I'd love to see current pics with your setup!