Looking for some large tank plumbing advice

[vol_reefer]

Wondering if some of the more experienced large reef tank owners could give me some plumbing advice. My wife and I are finishing the basement in our house. One of the rooms down there will be a dedicated "fish room" - first to support our current 150 gallon reef, but in a couple years we're planning to upgrade to around 500 gallons. The fish room will contain the sump, skimmer, chiller, frag grow out tank, etc.

I'm planning to use FlexPVC (Spa Flex) hoses to run between the upstairs tank locations and the fish room for drain and return lines. I realize standard PVC would be cheaper, but the lines have to turn a few corners and will be hidden in some ceiling cabinetry for part of their run to the fish room - the cabinets would be hard to work around with rigid pipes if I ever had to replace the pipes. The vertical drop between floors is probably 10 feet, and the horizontal run from either tank location to the fish room is about 35 feet.

For the existing 150 gal. tank, I'm planning to just use FlexPVC diameters that match the diameters of the braided clear hose I'm currently using to go to the sump in the stand - two 3/4" drain lines and one 1" return line (which splits into four locline nozzles in the tank). But I'm not exactly sure what diameters I should plan on for the future ~500 gal tank since I don't have the tank yet and haven't really done any detailed planning of how it will be designed. I've sort of been thinking that two 1.5" drains and two 1.5" return lines would probably be enough, but what do folks think? Is that actually too much? My local supplier is selling the 1.5" FlexPVC at $66 for a 50' roll, and 1" at $40 for a 50' roll, so if I could get away with smaller diameters it would save me a little money (not a huge concern in the scope of things, though). Most of the pumps I've looked at that would be appropriate for this size tank have 1.5" outputs, so that's why I was leaning toward that diameter for the returns (I'm thinking two pumps, each with its own 1.5" return line for redundancy). In my simple-mided logic about plumbing, it sort of makes sense to me that the drain lines should have at least the same total cross-sectional area as the return lines so that the drains can keep up with the return.

Many thanks to anyone who can provide the benefit of their experience. I need to make a decision on this by Monday or Tuesday (the contractor is almost ready to sheetrock - kind of snuck up on me), so if you have some ideas, please let me know soon!

Jeff (vol_reefer)

 

[waynem]

I would add a third return if your going with 2 pumps, your follow back will have problems otherwise. It depends on how you do your overflow but to try and get gravity to push the water back in the same dia pipe at the same volume is hard to do.

 

[vol_reefer]

<a href=showthread.php?s=&postid=14851713#post14851713 target=_blank>Originally posted</a> by waynem
I would add a third return if your going with 2 pumps, your follow back will have problems otherwise. It depends on how you do your overflow but to try and get gravity to push the water back in the same dia pipe at the same volume is hard to do.

OK - thanks. That makes sense. So would three 1.5" drains and two 1.5" returns be probably be sufficient for a ~500 gal. tank then?

Jeff (vol_reefer)

 

[pclausen]

I have a 180g and a 150g upstairs in the living room, both connected to a common sump in a fish room in the basement. The 180 has a single 2" drain and a single 1.5" return. The 150 is tee-ed into the 180 plumbing in the ceiling just outside the fish room, using 1.5" for both the return and drain.

I run a single Sequence Hammerhead wide open from my sump back to the tanks. My 2" drain is having no issues keeping up, nor is the single 1.5" leg on the 150g tank.

I used rigid piping with swept elbows for everything. I got about a 10' drop and the 180 is about 20' from the fishroom, the 150 about 30'.

 

[psteeleb]

A couple thougts

Design the layout for your drains first. If you can avoid the spay flex in long horizontal runs, it sags causing air traps that will make the water surge and make noise. The best advice I can give on drains is to think of a water slide in a tube. Minimize your changes in direction and provide a 1/8" to 1/4" per foot slope in the line.

Next, keep you pump suction piping as short and direct as possible. Changes in direction cause turbidity, this turbidity as it enters a pump can cause cavitation, hence air bubbles.

On the returns spa flex is fine to minimize fitting friction loss. Increase at least one pipe size from the pump discharge especially for long runs as this reduces friction (head loss) in the pipe

HTH and good luck

 

[vol_reefer]

Peter, psteeleb,

Thanks for the help. One of my local club members reminded me about the flow calculators here on RC, so I ran some numbers on those. I also talked with Chris at Reeflo to get his take. It seems like the best option will be two have two 1.5" return lines, each using Barracudas. For the drains, I could probably get away with three 1.5" lines, but might instead go with four 1.5" lines, just to have a little extra capacity. The difference in flow resistance between the 1" and 1.5" lines is pretty amazing - definitely worth the extra bump in cost to go with the 1.5".

psteeleb, I appreciate what you said about the trades on rigid vs. spaflex. I think if I use hanging loops spaced close enough together, I can avoid getting too much sagging. The problem with going with the rigid pipe is that these lines will be buried in some ceiling cabinetry and I'd have to hack them all up if I needed to get them out to replace them. I'd rather try to avoid any joints or couplers in the pipes just to avoid any chance of leaks (these cabinets aren't cheap!), so going with a single unbroken spaflex pipe for each line seems to make more sense.

Jeff (vol_reefer)

Jeff (vol_reefer)