confused about flow

monotreme_man · 05/28/2009, 12:32 PM

i have a 200gal flat hex.

currently, i have 3 maxi-jet 1200 with the sea-flo mods for what
is putatively around 4000gph (i'm not real sure if this means
anything concrete but i can do the math). i have the heads arranged
such that the water flow forms a gyre circulating widdershins
(counterclockwise), because the latest paper on water flow
i read argued for greater laminar flow (you get turbulent flow
when this laminar flow hits rocks and obstructions).

i am reticent to upgrade powerheads because frankly, the next step
i would be willing to take would involve tunze's or vortechs, which
i would need 2 or 3 at $300+ each.

i would be willing to deploy 3 more of the same maxijets and arrange
them to circulate deisiel (clockwise) and arrange a timer to switch between
them (every 30 mins maybe).

is this madness? or stupid? it does seem contrary to the standard opinions
expressed here. for what its worth, i normally find when i'm snorkelling on the
reef (great barrier, belize, bahamas, st johns), the flow is nearly always
weak to strong tidal (hence laminar) flow.

mg426 · 05/28/2009, 12:40 PM

Depending on what type of Corals you are planning to keep 4000 gallons in a 200 gallon type may be on the low side. As for MJ powerheads/kits I have run them forever.Are they the best? No way. Are they reliable, cheap,and easy to use? Aboslutley. As for your flow arrangement, Now that is a loaded question. Flow in my opinion is the most time consuming, frustrating thing one must consider when setting up a reef. Trial and error and seeing how your corals react will most likey go a long way toward telling you when you have got it right.

Sisterlimonpot · 05/28/2009, 12:44 PM

In a hex tank I don't know if you want to create a circular motion of flow whether it be widdershins or deisiel, I would point them in a manner to where the create pretty good turbulence and allow for some good surface agitation.
You say that you have 3 maxijets with the sure flow mod. Those should rate 2100 GPH (white prop) each, unless you have the black props. the white ones work well with the 1200....

sometimes. but that's another issue.

reefscape15 · 05/28/2009, 07:55 PM

I agree with just playing with different setups instead of looking for an answer. You will have a much better idea of what works in your tank than anyone else will. Keep an eye on how your corals react to the different types of flow and just try to find what works

monotreme_man · 05/28/2009, 07:58 PM

well, i said sea-flo which are rated by them at 1200-1400.
and a flat hex is largely equivalent to a rectangular tank,
but i digress.

i guess, as mg426 said, the proof of teh pudding is in the eating.
i was hoping other people had tried something other than point
powerheads at or near each other (oversimplification, i know).

walkthedog · 05/29/2009, 12:43 PM

Your question is hard to answer because there are so many ways to get good flow in a tank. Depending on your budget and how many powerheads you want in a tank. I myself would not want 6 powerheads in a tank unless I could hide them within the rockwork. I don't know how long your tank is but that would help a little with giving suggestions. The best flow IMO is random indirect flow. How you can get this done is up to you. The more you pay the less powerheads you will need. Also less powerheads means less heat transfer into the tank. Depending on your lights this can make a big difference. A wavebox is also a good way to get movement in a tank but can cost a lot of green. What is the L and W of the tank? What is in the tank LPS, SPS, mixed?

monotreme_man · 05/29/2009, 12:59 PM

it will be mixed. heat is not a problem (i use T5 lighting and having the
sump in a basement naturally cools things). i am not hugely fond of
powerheads but i have 3 right now and they are acceptable.

the tank is roughly 84x24x24.

walkthedog · 05/29/2009, 02:45 PM

7 foot tank. I would try a wave box. It will give you great movement. You can find them used in the trading forums so won't break the bank too bad. It will greatly improve the total movement in the tank. With 7 feet to cover the wave won't be that high. Once you find the right frequency the movement feeds off the last wave. It will cost you about 300-350 $ for a used one or you can DIY. In a mixed reef the movement is great and you don't have powerheads everywhere. Use your 3 powerheads to target areas of the tank that need more flow (hard corals) and it should do the job well. There are some u tube clips with waveboxs that can show you what the movement looks like if you haven't seen them in action.

05/28/2009, 12:32 PM	#1
monotreme_man Registered Member Join Date: Aug 2008 Location: Southern California Posts: 228	confused about flow i have a 200gal flat hex. currently, i have 3 maxi-jet 1200 with the sea-flo mods for what is putatively around 4000gph (i'm not real sure if this means anything concrete but i can do the math). i have the heads arranged such that the water flow forms a gyre circulating widdershins (counterclockwise), because the latest paper on water flow i read argued for greater laminar flow (you get turbulent flow when this laminar flow hits rocks and obstructions). i am reticent to upgrade powerheads because frankly, the next step i would be willing to take would involve tunze's or vortechs, which i would need 2 or 3 at $300+ each. i would be willing to deploy 3 more of the same maxijets and arrange them to circulate deisiel (clockwise) and arrange a timer to switch between them (every 30 mins maybe). is this madness? or stupid? it does seem contrary to the standard opinions expressed here. for what its worth, i normally find when i'm snorkelling on the reef (great barrier, belize, bahamas, st johns), the flow is nearly always weak to strong tidal (hence laminar) flow.

05/28/2009, 12:40 PM	#2
mg426 Registered Member Join Date: Jan 2006 Location: maryland Posts: 6,923	Depending on what type of Corals you are planning to keep 4000 gallons in a 200 gallon type may be on the low side. As for MJ powerheads/kits I have run them forever.Are they the best? No way. Are they reliable, cheap,and easy to use? Aboslutley. As for your flow arrangement, Now that is a loaded question. Flow in my opinion is the most time consuming, frustrating thing one must consider when setting up a reef. Trial and error and seeing how your corals react will most likey go a long way toward telling you when you have got it right. __________________ I found a way to make a small fortune running a reef tank. Start with a large fortune. Unofficial President of the SEACLONE haters club Current Tank Info: 125 mixed reef 110 lbs LR, 1x250watt XM 20K MH 2x175watt XM 20K MH on Magetics 2X96 watt actinic PC, 220 watt VHO actinic, 30 gallon refugium, closed loop system powered by Sequence Dart MSX 200 skimmer 38 gallon sump, Oceansmotions squirt

05/28/2009, 12:44 PM	#3
Sisterlimonpot R.C. Fraternity President Join Date: Dec 2008 Location: Litchfeild Park AZ Posts: 11,490 Blog Entries: 2	In a hex tank I don't know if you want to create a circular motion of flow whether it be widdershins or deisiel, I would point them in a manner to where the create pretty good turbulence and allow for some good surface agitation. You say that you have 3 maxijets with the sure flow mod. Those should rate 2100 GPH (white prop) each, unless you have the black props. the white ones work well with the 1200.... sometimes. but that's another issue. __________________ Jimmy MASVC President Dishes are done man! Current Tank Info: 300 in progress

05/28/2009, 07:55 PM	#4
reefscape15 Registered Member Join Date: Jan 2009 Location: Elmira Heights, NY Posts: 2,812	I agree with just playing with different setups instead of looking for an answer. You will have a much better idea of what works in your tank than anyone else will. Keep an eye on how your corals react to the different types of flow and just try to find what works __________________ A new beginning........... JIM Current Tank Info: 5g standard softie/zoa tank, just starting a 20H

05/28/2009, 07:58 PM	#5
monotreme_man Registered Member Join Date: Aug 2008 Location: Southern California Posts: 228	well, i said sea-flo which are rated by them at 1200-1400. and a flat hex is largely equivalent to a rectangular tank, but i digress. i guess, as mg426 said, the proof of teh pudding is in the eating. i was hoping other people had tried something other than point powerheads at or near each other (oversimplification, i know).

05/29/2009, 12:43 PM	#6
walkthedog Registered Member Join Date: Dec 2008 Location: Charlotte,NC Posts: 370	Your question is hard to answer because there are so many ways to get good flow in a tank. Depending on your budget and how many powerheads you want in a tank. I myself would not want 6 powerheads in a tank unless I could hide them within the rockwork. I don't know how long your tank is but that would help a little with giving suggestions. The best flow IMO is random indirect flow. How you can get this done is up to you. The more you pay the less powerheads you will need. Also less powerheads means less heat transfer into the tank. Depending on your lights this can make a big difference. A wavebox is also a good way to get movement in a tank but can cost a lot of green. What is the L and W of the tank? What is in the tank LPS, SPS, mixed?

05/29/2009, 12:59 PM	#7
monotreme_man Registered Member Join Date: Aug 2008 Location: Southern California Posts: 228	it will be mixed. heat is not a problem (i use T5 lighting and having the sump in a basement naturally cools things). i am not hugely fond of powerheads but i have 3 right now and they are acceptable. the tank is roughly 84x24x24.

05/29/2009, 02:45 PM	#8
walkthedog Registered Member Join Date: Dec 2008 Location: Charlotte,NC Posts: 370	7 foot tank. I would try a wave box. It will give you great movement. You can find them used in the trading forums so won't break the bank too bad. It will greatly improve the total movement in the tank. With 7 feet to cover the wave won't be that high. Once you find the right frequency the movement feeds off the last wave. It will cost you about 300-350 $ for a used one or you can DIY. In a mixed reef the movement is great and you don't have powerheads everywhere. Use your 3 powerheads to target areas of the tank that need more flow (hard corals) and it should do the job well. There are some u tube clips with waveboxs that can show you what the movement looks like if you haven't seen them in action.