First salt water tank. Did I miss anything?

[johnny roastbeef]

You really cant have too much flow. Having said that, if the flow is so strong that it causes a sand storm, or if it batters your corals, then it IS too strong. Remember wave action on the coral reefs is pretty violent and confused.

Purple up is a great way to 'see' the flow, and get a little calcium in the tank at the same time. Just drop a capful at one end of tank, and watch the path it takes while it disperses. You can also put some in a baster or dropper and release it along the bottom and corners of the tank and see if it flows right away in the direction of the pumps, or if just slowly diffuses.

I have a 300 gallon display with a 150 gallon sump. The return is via 3500 GPH pump, I have an additional 2700 GPH closed loop providing circulation along the back of the tank, and MP40s on both ends of the tank providing an additional 3200 GPH each, and still I have an area of very low flow. I can tell because some Cyano is settling there, and it is obvious that the detritus is not blowing off the sand there. This week, I will be adding a second MP40 on that side of the tank, towards the bottom.

Remember the rocks will deflect and slow down any water flow in the tank.

 

[Chaz88]

Thanks for all the help. The almost instant feed back you can get on the net is way better than old days of S.W.A.G, head scratching and frustration it took to figure it all out on my own.

Couple more questions.... On my fresh water tanks I consider most things added to the tank a negative when it comes to displaced water volume. Am I correct in assuming live rock basically pays for itself when it comes to displacing water volume? If so, at what point dose it become a matter of diminishing returns?

Also, I have no immediate plans for live corals. With just live rock and fish, do I still have the same water circulation requirements? I don't have a problem adding what is needed or even a bit more. I just don't want to throw money at equipment and electricity if it is not beneficial for my setup.

Thanks, Chaz

 

[johnny roastbeef]

Everything is a tradeoff. Lots of live rock would help more with bio filtration, but as you know the bacterial colony will only grow as large as the food supply, so completely filling a tank with rock and adding a damsel will just leave you with a lot of dead (or nearly dead) rock and no water for the fish to swim in. Someone came up with a number of 1.5 to 2 pounds of LR per gallon of tank volume. Thats a good place to start, but I usually add more. On the other hand the more water you have the more dilution you have and the easier it is to maintain. The tank will be more stable, take longer to build up levels of toxins, and be lest susceptible to salinity swings from evaporation.

You didnt mention whether you were running a sump. If not, you should really consider one. The largest you can fit under the stand. This will increase your water volume, give you a place for your skimmer, heater etc. and maybe even more rock.

Anyway back to flow. The real issue with flow is to make sure all the water circulates and is filtered. The rock provides all sorts of crevices for wast to accumulate, while blocking the movement of the water. In my system, for whatever reason, the right corner of the tank was getting no flow. By adding the new powerhead, I could see all the detritus kicked up and moved.

As long as you can see that there is water movement in all areas of the tank, thats all you need. Remember the water movement will also help to keep your rocks clean so they can do their job.

Back to the rock. The cost of rock can be outrageous. When I started, i bought 3 pieces at a local store and was horrified when they charged me $350. You dont have to pay that much, keep checking the reefing forums like reefcentral for locals selling their rock. I have around 500 lbs in my tank, and I bought at least half of it in little batches from other reefers at very reduced prices.