Bi- weekly discussion- Flow

[tims]

Well we talked about substrates, we talked about Live rock..
So i figure the next topic should be on flow.

My thoughts are hitting this in two areas. possible three .

what is flow, why is it important, is it really? what does it do for our tanks? for our corals?
Flow and parameters?

second part to happen a bit later on..
what ways can we give our tanks flow, ways to increase it. is 52x turn over too much? is 10x turn over too much?

Plaese feel free to answer and ask questions and jump in anytime!

[dobejazz]

Good discussion Tim!

[Geoff]

wooohooo, lets crank up the pumps!!

G~

[VWD]

Flow depend alot on what type of bio system you have, If you have a lagoon type system
it will be less then if You have a reef top sps set up, and then You have the in between, a tank with a mixture of the two,

[Geoff]

are you sure about that Vince? i think both can handle large amounts of flow. i think it is the velocity of the water that they can not handle.

G~

[Viv]

Well, wouldn't it depend on what you're keeping in the tank? I would imagine that high turnover is a good thing for corals like SPS, but corals that like a high nutrient load would prefer a lower turnover, allowing the nutrients in the water to stay in the tank water a bit longer.

[TheReefer12]

I think flow is one of the most important factors in my system. It keeps a lot of things from settling and causing problems and also adds oxygen to the water by causing ripples on the surface.

The flow also carries food from one part of the tank to the other. This is especially important for the filter feeders which depend on the food coming to them.

[scoop]

The flow seems to be a very big problem for a lot of people. In my tank it appears that the flow is the primary issue on whether or not I get hair algae. In the areas with a lot of flow, no problems, if there are any 'quiet' spots, small clumps of algae. I know the algae is caused by some other problem, but i still haven't found it.
What I'm dealing with now is that I can get enough flow ( I have a 28 gl tank w/ a 10 gl sump, ~40 lbs live rock, bb. Custom skimmer, 300 gph return, then for additional flow, 2 mj 1200's and 1 Sieo 620. If I run all 3 at the same time, the flow is strong and the detrius gets removed from the rocks pretty well. (I do weekly water changes, ~ 10 gal. and blast the rocks very thoroughly w/ a power head prior to each change. Hoever, w/in about 12 hours, the temp goes over 81, n ormally I keep it around 77. (no chiller) So I have put the 2 mj's on a timer where they alternate every 15 min., but then there doesn't seem to be enough flow to prevent getting spots where algae starts to grow. I have been working on this since about March of 2006 (I fought algae for over a yr before that.)
Anyway, long post, but short of buying a chiller, what are the alternatives?

[scoop]

One other flow issue/question? Unless I point 1 of my precious flow pumps or the return right on the surface, I don't get much agitation on the surace. I have enough to keep from getting accumulation of protiens, but it doesn't look like much. With the heat issue, do I really need a lot of surface agitation?

[theplatypus]

Originally Posted by scoop

One other flow issue/question? Unless I point 1 of my precious flow pumps or the return right on the surface, I don't get much agitation on the surace. I have enough to keep from getting accumulation of protiens, but it doesn't look like much. With the heat issue, do I really need a lot of surface agitation?

Here's a little discussion on tank surface area vs skimmer in regards to gas. exchange. Post #27 sums it up pretty well.
http://thereeftank.com/forums/showth...face+agitation

[theplatypus]

What is flow? It's our rather poor attempt at emulating the ebb and flow of the oceans tides. In nature and to some extent our tanks it provides an avenue for providing food and waste removal. I read somewhere on these boards that providing a whirlpool effect was the "best" setup for flow in our tanks. I completely disagree with this theory. Do waves break at the same point every time? In doing so is it with the same velocity? In my opinion the best possible flow would be random pattern. Both in timing and velocity.

[VWD]

Originally Posted by Geoff

are you sure about that Vince? i think both can handle large amounts of flow. i think it is the velocity of the water that they can not handle.

G~

I will give you that Geoff, On they both can handle good flow and need good flow, , and that it is velocity that they can't handle,


Trick Question

[Geoff]

Originally Posted by Viv

Well, wouldn't it depend on what you're keeping in the tank? I would imagine that high turnover is a good thing for corals like SPS, but corals that like a high nutrient load would prefer a lower turnover, allowing the nutrients in the water to stay in the tank water a bit longer.

why would a low turnover mean high nutrients? maybe a low turnover through the skimmer would equate to higher nutrients.

lets say i turn off my skimmer. my nutrient levels would go up correct. i will still have 100x turnover in my tank with the skimmer off. the nutrient level has changed but the flow has not.

nutrient levels and flow are different entities.

G~

[TheReefer12]

Flow does not take nutrients out of the water. Flow keeps the nutrients moving. The nutrients are taken out from the skimming process.

[theplatypus]

Originally Posted by TheReefer12

Flow does not take nutrients out of the water. Flow keeps the nutrients moving. The nutrients are taken out from the skimming process.

If you're referring to my waste removal comment you've misunderstood. Or I should have phrased it better. I wasn't inferring that it took it out of the water. Just kept it from building up in one location.