Low, Moderate, Strong

[Elricsfate]

I'm relatively new, and I'm trying to understand a few terms.

Descriptions of various corals refer to lighting in terms of low, moderate, and high. They use these same terms to talk about flow. But, they don't discuss what these terms actually mean.

Take a 1400 gph powerhead for example. In a 180g tank that might produce Moderate (ish) flow. In a 20 long I'd have to call that "high".

So my question is, is there a watt per gallon, or gallon per hour, rule of thumb I can use to approximate these measurements?

I have taken all of my coral frags and put them in a 20 because it is easier and less expensive to light the tank and grow them out prior to putting them in my display (which I will purchase nice lights for over the course of time). I put the LED I had available over the 20 (which atm is on black box, 100w 2 channel light). To my eyes it looks "bright". But without a par meter I do not know if the corals agree with me.

In fact, even WITH a par meter...what is considered "bright"?

Any help appreciated.

 

[Stolireef]

With regard to flow, high flow in a tank would be somewhere around 100x turnover per hour of total tank volume. By way of example, I have a 120 gallons total tank volume. I have two MP40s and two tunze 6095s. Maxed out, they can push over 100x turnover. I want to keep SPS so you need very strong water movement. 50X would be moderate and 25X would be low (of course, as with anything, opinions vary). Note that there are different types of water movement. All of my powerheads are designed to move large amounts of water with very wide flow (as opposed to pointing a small aperture powerhead that is more like pointing a hose). Also note that turbulent flow is usually preferred and that the return pump doesn't need to be super strong. Slower flow through a sump is usually preferred.

With regard to lighting, the reputable light manufacturers provide pretty good guidance. By way of example, according to EcoTech, two gen 4 radions would provide sufficient lighting in my tank to keep the most light demanding corals pretty much anywhere in my tank. I light my tank with 2x250 watt MH and 2 T5's. I should be able to keep any coral with those lights.

 

[Ron Reefman]

Flow is really tricky because as you stated, rates of flow vary so much based on the size of the tank and distance from the pump. It's really a lot of trial and error as well as personal experience. As Stolireef stated above, finding the total 'turnover' rate in the tank can be very helpful. And then you can find places in the tank where there is maximum flow (near a pump) and lower flow (away from pumps and protected from flow by rocks or other corals). My 125g tank has a total turnover of about 40 to 50 turnover flow rate (return pump, 2 wavemaker pumps and a CrossFlow laminar flow pump).

Lights are a bit easier as we can measure PAR at various points in the tank. So fairly accurate data can be determined for any fixture set at any power level and at any point in the tank. I know somebody, somewhere gave PAR levels that equate to low, moderate and high. IMHO, and kind of giving my best estimates, low would be 50 to 150 PAR, moderate would be 100 to 200 PAR and high would be 150 to 250 PAR. I know some high light corals can tolerate PAR higher than 250, but I'm not sure it's all that necessary.

Again, these are just my best estimates based on reading, my memory and my experience. Others may have better real data. I hope that helps a little?

 

[Elricsfate]

Flow is really tricky because as you stated, rates of flow vary so much based on the size of the tank and distance from the pump. It's really a lot of trial and error as well as personal experience. As Stolireef stated above, finding the total 'turnover' rate in the tank can be very helpful. And then you can find places in the tank where there is maximum flow (near a pump) and lower flow (away from pumps and protected from flow by rocks or other corals). My 125g tank has a total turnover of about 40 to 50 turnover flow rate (return pump, 2 wavemaker pumps and a CrossFlow laminar flow pump).

Lights are a bit easier as we can measure PAR at various points in the tank. So fairly accurate data can be determined for any fixture set at any power level and at any point in the tank. I know somebody, somewhere gave PAR levels that equate to low, moderate and high. IMHO, and kind of giving my best estimates, low would be 50 to 150 PAR, moderate would be 100 to 200 PAR and high would be 150 to 250 PAR. I know some high light corals can tolerate PAR higher than 250, but I'm not sure it's all that necessary.

Again, these are just my best estimates based on reading, my memory and my experience. Others may have better real data. I hope that helps a little?

It does. It gives me a place to start.

Being newer, it's hard to look in the tank and think "That coral looks like it needs more/less light". Especially if I don't know how much light I'm providing to start with.

I guess I'll drop a couple bucks on the Seneye and get some readings.

 

[Stolireef]

I really wouldn't bother with a PAR meter. You don't need one. There are so many solid lighting solutions that will work to keep even the most demanding corals. T5s, MH/T5s, MH, LEDs, hybrids, etc. All will work fine to keep corals. You adjust the intensity by placing the corals higher or lower in the tank (with LED's you have more options). If a coral requires high light, just place it higher in the tank.

 

[Elricsfate]

I really wouldn't bother with a PAR meter. You don't need one. There are so many solid lighting solutions that will work to keep even the most demanding corals. T5s, MH/T5s, MH, LEDs, hybrids, etc. All will work fine to keep corals. You adjust the intensity by placing the corals higher or lower in the tank (with LED's you have more options). If a coral requires high light, just place it higher in the tank.

Well the problem is I am not keeping the demanding corals. I have leathers, mushrooms, zoas, a sea fan, and a few star polyps. So my problem is that they need from moderate lighting to low lighting.

Basically I need to get the levels to acceptable for the highest need corals I have, and then move the others to the edge, or shade them in some way. But it would be helpful for me to know what the par is at the center, and then position the corals accordingly.

Also, I have them all sitting on small rocks in a bare 20. So there is no rockwork to raise them up or down on.

I will ponder different approaches prior to spending the money.

 

[mcgyvr]

I really wouldn't bother with a PAR meter. You don't need one. There are so many solid lighting solutions that will work to keep even the most demanding corals. T5s, MH/T5s, MH, LEDs, hybrids, etc. All will work fine to keep corals. You adjust the intensity by placing the corals higher or lower in the tank (with LED's you have more options). If a coral requires high light, just place it higher in the tank.

Frankly I think more people should have one (just sad that the costs haven't come down)..
I'd be willing to bet quite a bit of money that a vast majority of people are actually providing much more light than needed..

I've seen some AMAZING tanks in person and thought.. Holy cow.. Thats really dim looking.. That surely can't be enough light.. But the corals speak for themselves..


But yes.. you can certainly get by without one..

 

[Ron Reefman]

Frankly I think more people should have one (just sad that the costs haven't come down)..
I'd be willing to bet quite a bit of money that a vast majority of people are actually providing much more light than needed..

I've seen some AMAZING tanks in person and thought.. Holy cow.. Thats really dim looking.. That surely can't be enough light.. But the corals speak for themselves..

But yes.. you can certainly get by without one..

I tend to agree with everything mcgyvr had to say. Many run with more light than they need, especially with leds. And really no need for a PAR meter.

Tell people 3 things:
1) What brand/model of led you have
2) The dimensions of your tank (especially how deep)
3) What kind of corals you are keeping

With that info, others with similar fixtures and similar tanks and similar corals will jump in and tell you what they are doing. This should be about all you need to do.