On zoas and flow

[RonMidtownStomp]

I've recently started keeping up with this forum and I've noticed a theme of people spending a lot time talking about the amount of flow and amount of light provided a certain zoa or paly. I'd like to open up a discussion on how you define "high flow," "low flow" and how you define "high light" and "low light."

Some background -- I've used a PAR meter to take some base measurements and I've found that with my 20K Radiums I get about 200 PAR at the bottom of the 2' tank and at the top I get about 1k PAR. I have massive amounts of flow throughout all of my tanks. I define this as a Tunze 6100 on the 30 gallon zoa frag tank and as a Barracuda closed loop plus a Tunze 6100 on the display tank. I run a Tunze 6100, another smaller Tunze and two K4's on the 100 gallon frag tank.

Only recently did I ever think, "that might be too much flows for those zoas" when I moved a rock with a colony of Tyree Blue Eye Girls right directly in front of the Tunze 6100. The colony is receiving the full force of the Tunze 6100 at about 1" distance and has never looked better.

As far as light, I'm trying to figure out if I have any zoas or pallys that I don't think look better under high light and I come to the conclusion that I can not think of any. Perhaps a couple of my corals lose some of their speckles, and I've always blamed the Pink Zippers for not looking like the ones from Who Dah on them being false, not on the light. We'll see what happens to the Pink Zippers I got from Who Dah last week after they're under high light for a while. So far they are speckled.

Thoughts?

Ron

 

[jbell370]

I recently changed from a 150w 10K HQI to a 20K. I know the bulb is still in a break-in period, but I have noticed after the past week the colors do pop more, I am still waiting to see how this will change the growth the Zoa's though if any at all.

As for flow, I have a Marineland 60g cube, 24x24x24 with 300 gph return and 2 Koralia Evo's pushing 750gph so ruffly 30x flow through the tank. I have not tried any more or less flow, but every head opens up and stays open throughout the day, so the flow does not seem to harm them any.

 

[RonMidtownStomp]

As far as your lighting change, PAR is the way of measuring light usable by the corals to produce energy they need to grow. There is a lot more to a bulb than the color temp rating. However, the change from 10k to 20k usually means that you have reduced the PAR readings. My theory is that a coral can only utilize so much light per day, so I believe it's unlikely to have a dramatic effect and I will not likely us anything but 20k bulbs again.

Interestingly, the PAR produced by my 250W Radiums when measured above the surface of the water was almost identical to the PAR reading I got when I walked outside and pointed the sensor at the sun.

Ron

 

[Scopus Tang]

Excellent start to what hopefully will become a great thread - truly one of the issues I've started delving into as well. The research I've done would indicate that in many cases, water flow may actually be far more important to the corals than light; uptake of oxygen, removal of wastes etc. I personally am running a 65 gallon with a 20 gallon sump. The return pump is a QuietOne 4000, and I've got two K2s, two K1s in the DT and two K-nanos in the sump.

Ignoring the nanos (since overturn in the sump doesn't really count) and dropping the return pump a bit for head height, lets say about 2100 gallons per hour, so about 32X turnover, maybe a little more since the 65 doesn't truly hold 65 gallons of water.

I've been thinking lately that I need to up the flow as I appear to have dead spots in areas that leds to accumulation of cyano on the polyps, causing them to close up and stay closed. Moving frags around directly into higher flow areas helps, but sometimes too much flow can cause the polyps to remain closed as well.

My thoughts to the OP would be that just as corals can acclimate to higher lighting, they can also adjust to higher flow - I have Devil's Armor polyps that have long wavy skirts because of the high flow rate in the area they are located.

However, I do think that unless or until they adjust, there is such a thing as too much flow - such as being placed directly in front of a powerhead.

As the for the lighting, I can tell you that there is indeed such a thing as too much light. True Red and True Green PE will both lose the bluish inner disc if exposed to too much light. And other polyps will bleach out and lose their color. Again, in my opinion, I think the big issue is acclimation. I've seen polyps growing in tanks with two 400w MH lights over an 24 inch deep tank, and they look great.