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View Full Version : Flow rate fore feeding time.


Abalone joe
08/08/2006, 12:21 AM
I'm setting up my 29G. The total system circulation including sump return & closed loop will be around 35 x turnover. How do I go about feeding the fish without being able to slow down the pumps? Even If I turn off the Closed loop I'll still have a 20X turnover. I'm just concerned trhe water will carry the food around so fast the fish won't be able to catch the food as it fly's around the tank. Probably thru the rock's and decorations.

pnosko
08/08/2006, 12:38 AM
You could just turn them all off for a short while. OTOH, 35gph doesn't sound like very much of a problem for feeding-- it's just a little above 1X, so I'm not sure how you got 20X w/o the closed loop running.

Abalone joe
08/08/2006, 12:46 AM
I'm sorry, I meant 35 Times turnover. I edited my post to correct the mistake. This is my first reef tank. How do most people deal with this issue.

pnosko
08/08/2006, 07:55 AM
I built a feeding timer where I would manually turn off all/selected pumps and when the timer expired, they would turn back on automatically. It's not a difficult project if you're handy with wiring and such.

Here's the thread from when I built mine. Let me know (here) if you're interested in building one and need more info. Some of the pic links in that thread are broken.

http://reefcentral.com/forums/showthread.php?s=&threadid=77348

Abalone joe
08/08/2006, 08:26 AM
I am interested. Problem- Even if I turn off my closed loop, The main system pump will still be running. That's still a 20x turnover of the tank volume. I really don't know if it's a good idea to turn off both pumps.
Another side issue is that I'm getting a little tapped out on cash. If there's another solution that doesn't involve yet more equipment. That may ease my situation a bit.
That being said. Just because I'm asking for another solution I would still also be interested in the off timer. It seems very useful for the $ spent. Also, how confident are you on the safety of the electrical work. I noticesd there was some concern about the proper relays. Of course I don't even know how a relay operates. I just noticed some warnings in the listed thead.

pnosko
08/08/2006, 08:40 AM
The relay just reverses the funtioning of a timer from ON while "timing" to OFF while timing.

Why do you not think it's a good idea to turn off all pump just temporarily? The cheap solution is to turn them all off and back on manually.

Abalone joe
08/08/2006, 08:48 AM
It just seems unhealthy. May cause water stagnation problems. Admittedly minor, I just though consistant flow, at least at some level, would be preferable.
Do you have a schematic?

pnosko
08/08/2006, 10:14 AM
No, but I believe the relay comes with one.

flameangel88
08/08/2006, 10:18 AM
You can put a small powerhead in there for feeding time use and that way the food doesn't just sink to the bottom.

meco65
08/08/2006, 10:37 AM
I just unplug my pumps at feeding time. You just have to remimber to plug them back in.

pactrop
08/08/2006, 11:01 AM
Isn't it pretty hard on your pumps to be turning them off and on all the time?

flameangel88
08/08/2006, 01:03 PM
I power off the skimmer pump and I shut the Tunze off with the meal time switch otherwise a lot of the food will go into the skimmer and get blown all over by the Tunze pump. But I let the other power heads run to keep some flow going.

I only power off twice a day and the Tunze 6000 & MJ are designed for use on wavemakers so I think it will not be too hard on them. JMO

4MB
08/08/2006, 02:39 PM
In my 30 I have like 32 x turnover or something. I just let the powerheads keep running. As all the food scatters so do the fish and it actually allows my sand sifter to get food as the other 4 are off chasing food. It eventually blows back by and he snags it.

Abalone joe
08/09/2006, 06:46 AM
With a setup in which the pumps are left on continously; Will the fish be able to catch enough food to be satisfied? I understand that I may have some food caught in the skimmer, But I mostly concerned with my fish getting enough food without without having to dump major amounts of the food in the tank.
Also, I was at my lfs and spoke to one of the old salts. I'm going to be running CPs so I won't be keeping any sps except possibly some montipora or some of the other more easy going sps species. I was thinking of limiting my circulation to the main system pump returned thru the Calfo advocated manifold. This would leave me with around 610gph or about 20x for a turnover. Keep this in mond when considering the first two questions posed.

pnosko
08/09/2006, 07:11 AM
I think your worry is 20x the problem. I don't see how a few minutes of pump inactivity for each feeding can have any adverse effect on your tank. This site is filled with pictures of gorgeous SPS-filled tanks with reflections from the still surface-- all pumps were turn off and the water allowed to still to get good pictures.

That said, the water movement on real reefs dwarfs that in our tanks. And it never stops, does it?

Abalone joe
08/09/2006, 07:48 AM
Right. I totally agree with that assesment. The pumps being temporairily turned off probably wouldn't be that bad. I do worry to much. I guess it's just genetic prediposition together with watching the news all my life as the eviromental que to be a worry wart.
I think pump ware may be an issue. Especially at a high amount of head. I just tried the head calculator from the link on the main page. The QO 3000 would only give me a flow of 322 GPH or just over a 10x turnover.
That was a fairly quik estimate of my planned plumbing. I'll have to do it again but be more precise with my measurements. Whatever the end result; It looks as if I have grossly underestimated my probable head loss. Take a look at the Head loss calculator form and picture it in relation to a manifold setup. Do you count Tees as 90 degree elbows? Also; It seems to take the manifold idea into account because it asks for the number of outlets. Do you really include all the horizontal sections of the manifold itself as head to be lost? That's rough.