Multi-Tanks and the laws of Physics

[olivesaxer]

hey guys,

this is my first posting... but i have been lurking about the fathoms of these forums for a time now.

question is about multiple tanks on a single wet/dry sump... i know a few of you have done it, so this question is specifically to you.

i have:
135 gallon glass tank
55 gallon glass tank
25 gallon glass tank


I desire:
to convert my 25 into a sump-styled wet dry for both my 55 and my 135. The 55 to be a planted aquarium with nothing but black ghosts (they look so wicked in the leaves!) and my 135 into a stone and fin tank for my other fishies.

the thought of daisy-chaining my tanks together kind-of scares me seeing as how the surface area of my 135 is quite large and would easily flood over my 55 given a single pump failure... So, i thought that perhaps if i ran two identicle pumps out of my return chamber of the 25 gal. pump, this would keep each tank more or less independant, and if a pump fails, i would have a single-tank overflow flood rather than my 135 overflowing to my 55 (due to gravity) overflowing to my sump...

is my thinking correct here? i want a single water system with multiple "channels"...

i haven't been able to find too much information on multiple tank systems other than "oh, i am going to do it" and not "how" it is to be done.

any thoughts?

-Patrick

 

[olivesaxer]

oh, and i really don't want them to be at the same physical water level, because that would put my 55 up way too high to be enjoyable.

also, would i have problems with backflow through the overflow from the 55 to the sump if i have the 135 pouring down as well?

 

[vidiots]

Well the Top tanks over flow to the sump. If water stops being pumped into the top tanks they stop overflowing to the sump. The water that is trapped in the plumbing between the top tanks and the sump will drain down into the sump. Because the sump is not sealed air tight water will not form a syphon to travel from one top tank to the other top tank thru the sump. The overflows in the top tanks are placed near waters surface so that the top tanks can't completely drain themselves. You need to have a tiny hole in your return from the sump that is above or just barely below the water line in the top tank to prevent it from syphoning down to the sump in the event of pump power loss.

I currently only have one tank attached to my sump, but would like to attach more in the future. Should just be a matter of putting another tank with an overflow above the level of the sump and plumbing the overflow into the sump, then adding another pump to the sump that is plumbed up to the return of the new tank.

You might have the water level and syphoning issues you are affraid of if you were to try to just "T" off the one pump to multiple tanks. I'm fairly sure you'd have to have a seperate return pump for each tank.

As far as over flowing your sump with all the drain back, the sump needs to have enough room to hold all of the water that will drain back from the plumbing when the power goes out. You determine the water level in your sump, gotta be deep enough to keep submersible pumps under water, but shallow enough to hold the drain back.
Lets say that with the pumps running you fill your 25gal halfway. Shut the pumps off and you have room for 12.5 gals to drain back into the sump.

One of the things I did was put an overflow near the top of my sump that runs into the house drain pipe. Now all I have to do is add water to my sump to do a water change, the excess water overflows into the drain. To automate water changes you can just use a cheap garden hose timer/solenoid valve running into the sump. Just gotta limit the duration or the flow rate the hose is on when adding all cold water so that you don't drop the temp in the tank too much.

 

[Sploke]

I'm designing a multi-tank sump setup that will run about 6 tanks. I'm not sure what your setup is going to look like, but to use overflows, both tanks need to be higher than the sump. What I would do is put separate overflows on each tank that can join together at a lower level, that drains into the sump. Then, you can use one pump and split the plumbing off so a line goes to each tank. Then, put ball valves on each of the two return lines and adjust to get appropriate flow to each tank.

As long as the sump is lower than both tanks, you won't have one tank draining into the other because the lower tank will always want to drain into the even lower sump. The only issue would be a 25gal tank is a pretty small tank to use for a sump for that much water volume, if your power cut off it would be likely to overflow.

 

[Squawkbert]

^ what they said (though I'd be inclined to use 2 pumps as the tanks are very different in terms of size).

All I really wanted to add is a suggestion to ad a stout UV (good) or ozinizer (better, IMHO) unit to the sump so that you minimize the risk of spreading bugs from one tank to the other(s) via the sump.

 

[ThePBM]

frankly your 25 is a bit small to be a sump even only for the 135.
it may sound awkward to you, but if anything, you should use your 55 as a sump and the 135 and 25's as tanks.

 

[vidiots]

frankly your 25 is a bit small to be a sump even only for the 135.
it may sound awkward to you, but if anything, you should use your 55 as a sump and the 135 and 25's as tanks.

Although I agree that the bigger sump would be better, I have been sucessfully using a 20gal High tank as a sump for my 180gal tank for the past couple of years. The down side of the smaller sump is that it requires more frequent maintenance. I have to clean the filter foam in mine about every 3 months to prevent it from becomming clogged and getting bypassed by water flowing over it instead of through it. It's setup like a Hamburg Mattenfilter with the 20g tank divided in half lengthwise. It works out to be the bare minimum in terms of bio-media surface area for this type of filter for a tank that large.

I can get away with the bare minimum as my setup because the 180 is lightly stocked with fish and heavily planted with live plants which do the majority of the biofiltration, and the mattenfilter is just a "backup" system for plant biofiltration.

 

[olivesaxer]

UPDATE:

Ok, so I decided against the 25 for sump. I ran the numbers to determine the volume of 1 inch of water from all of my tanks and it just wouldn't work. (as some of you predicted).

I did have a 35 gallon around that i had planned on using for another project... so after 600 dollars in parts (and black rocks), my 135 is now bubbling away on a sump finally. No fishies yet (see GENOCIDE!!! in the generic freshwater section), and no multiple tanks yet. My roommate and his girlfriend are getting into this hobby, so I might just put the 25 in another room and throw some guppies in it to have them have something to talk about.

I am really pleased with the way it is looking so far, and will put some pictures up later today with the plans on how to add the other tank. Craigslist has become my second home on the internet, and i will be tracking down another after my checkbook heals from this little adventure.


-Patrick