Slow or No Growth

Hello Reefers,

My 50 gallon reef has been up and running for 2 years now. I started with an established tank that I purchased that was running a 4 bulb (39 x 4) T5 fixture. It did not have many soft corals other than some Xenia (pop-pom coral) and some small mushrooms. I wanted to get some good growth and be able to get some nice colored softies but I was told I needed more light. So, I went and found a MH 2 x 150 watt setup with 2 actinics CF bulbs. Long story short, not much in the way of growth 8 months later.

My water quality is

PH 8.2
Ammonia 0
Nitrate/Nitrite 0
Phos .5
KH 10 (140-200ppm)
Temp 77
Cal is a bit high at 520 but my water change brings it down every 2 weeks.

I have a chance to go back to T5 lighting a 6 bulb fixture that is 18 width as my tank. More light spread I would think.

Any thoughts as to why I am not getting growth like I see in other reef tanks? My filtration is a Remore (hob) Protein Skimmer and an AquaClear 70 (hob) filter with sponge and bio media.

For fish, I have a mated trio of Maroon Clowns, a Yellow Tang, a Copperband and 2 small yellowtail Damsels.

Thanks,

LoveMyReef

 

First off I would of stayed with the t-5 that is enough for softies IMO MH are kinda old school. What do you feed the tank. It could be they need some food as your water seams fine.

 

What about your mag?

 

If you are doing softies only you may only need 2 T5HO bulbs. I would let my nitrates go up and lower my phosphate some. Also let your Ca get down to 420. If you are not feeding the corals start doing so. Coral frenzy or something similar would be good.

 

+1 To phosphate and magnesium. Phosphate has been known to promote algae and growth and inhibit coral growth. I would not go out and buy a phosphate test kit, they are unreliable and impossible to read. I usually judge my phosphate levels on how much algae is growing in my tank. Although I recommend a digital tester, we are not all so fortunate to be able to afford this on top of everything else. A GFO reactor may do the trick.

You should also check your magnesium levels. You could have all the calcium and alkalinity you want, but they are worthless without the proper level of magnesium. In order for your corals to be able to actually use the Ca and Alk, your Mag level should be approximately 4 times your calcium level.

Hope that helps! Good luck!

 

Is your calcium always that high between water changes? Are you dosing anything?

 

Yup.

 

are you feeding your corals?

 

Thank you all for the great advice and tips. I know all my water levels except Mag and Alk. I will take some samples to my LFS and have them test them until I can get a kit of my own.

I am feeding corals Cyclop-eeze frozen bar and what use to feed fish, prime reef flakes, brine shrimp and small formula one reef pellets.

I will advice test results later today.

 

What is in the tank anything other than softies? It sounded like this is a softie tank? If it's a mixed reef, I think gabbyr189s comments were a good start, however, if softie only, they should be appended a bit.

Re: growth that's skeletal growth in stony coral not soft corals.
As for algae, that's true, it can promote algae growth and algae growth. Also, algae can release carbon byproducts, which promote bacterial growth, which can kill corals. However, softcorals tend to do better with high bacterial counts then stony corals.

Agree for stony corals, but phosphate isn't as much of an issue with soft corals. GFO may be too aggressive for a softcoral tank. However, it's tough to say without knowing the level. The Hanna phosphate checker, or better ultra-low range phosphorous checker work well for around $50. (note: phosphorous can be converted to phosphate by multiplying by 3.066 then dividing by 1000. The benefit is the Hanna phosphorous checker is more accurate than the phosphate checker.)

Very few soft corals are particularly sensitive to ca, alk and mg. A few are though, leathers especially, but you do not need super high levels, as you would in a stony coral tank.


For soft corals, in my experience, they tend to do better with lower light and lower flow. I had a 75g softcoral tank, which is still running elsewhere, for 10 years. I played with every sort of lighting and flow imaginable. What I found was it does best with 50-150 PAR. If your not familiar with PAR, PAR is a measure of light commonly used in the hobby. The 2 x150s are probably putting out about double that on a 50g, but it is tough to say. There are so many variables, such as reflector, bulb combinations etc... I would try to see if there is a local reef club around. Often they have a PAR meter for their members to borrow. Or perhapse a local reefer has one you can borrow.

As to flow. I have found the soft-corals tank does best with around 10x turnover. So, on a 50g, if you add up all the flow rating, of all your pumps, it should be somewhere around 500gph.

These are the two most important variables.

Next is nutrients. In a stony coral tank we try to keep nitrate and phosphate undetectable. For soft corals, I've found nitrate around 5-10ppm and phosphate slightly over .03 to be preferable. Nutrients help enhance tissue growth (they slow down skeletal growth, but soft corals don't have skeletons) Also, softcorals respond well to food. Feeding some phytoplankton to enhance natural food sources is useful. Also, increased fish feeding and fish poop will help directly and indirectly, as it will help drive bacteria, which is another important food source. Of course, with nutrients and feeding, it's always a delicate balance between nutrients and algae. A good cleanup crew can help with this though. Temperature is also helpful. You don't want the temp to be super high, but metabolism is linked to temperature. Higher temperatures will help with growth a bit. I find 78-82 to be a good range. try to make sure it stays below 84 though.