Slow growth in SPS tank

brad

New member
I had a tank crash in May which wiped out my SPS. My water parameters were terrible then (high Nitrate), but I had good growth. I have since restarted the tank, and added more frags. Water parameters are not great (need to measure and repost) but are better than they were before the crash. However growth is almost non-existent. I have 2 birdsnest frags which grew at first, but have since slowed down. I have about 8 acropora frags, I only lost one since restarting, but have had no growth from the others. I have about 40ppb Phosphate (Hanna ultra low), 5ppm Nitrate, Calcium around 400ppm and about 9 dKH. Something is using lots of calcium, as I am adding lots and it (and Alk) is falling fast, most likely a large squamosa I added, as none of my coral is larger than frag sized yet.

Could this be because I haven't had the tank running long enough? Or is PO4 to blame? I know it isn't the lights (DIY LED) because I had them before the crash.

I've also noticed almost no corraline growth (a good thing for me) since the crash. Before the crash, it was so out of control I had trouble seeing inside the tank even scraping weekly.

I have no soft corals that I didn't have before the crash, and lost most of the few I did have.
 

brad

New member
40 ppb phosphates = 0.040 ppm phosphates. This may or may not be slowing growth, and my Hanna tester may or may not be accurate.
 

animalkingdom

New member
40 ppb phosphates = 0.040 ppm phosphates. This may or may not be slowing growth, and my Hanna tester may or may not be accurate.

hanna ultra low reads in phosphorus not phosphates...did you convert to phosphates from phosphorus?? if the thingy read 40 that equates to 0.12 phosphates...
don't believe me look it up
 

brad

New member
I will check what it says and test again when I get a chance. However this is not relevant, unless you are suggesting a dramatic difference in growth between 0.12 ppm phosphates +/- the accuracy of this kit and 0.040 ppm phosphates.
 

brad

New member
So I reran my test this morning. Animalkingdom is right, it measures phosphorus and not phosphates. However it read 0. Either this is not that accurate, or I had briefly elevated phosphates due to it being a new tank, or both.

Has everyone responding actually had problems with phosphates? I've been doing this 12 years, rarely had measurable phosphates, never had measurable phosphates for an extended period of time, and never noticed any correlation between phosphates and growth.
 

ksicard

New member
.12 is on the high side but it wouldn't cause a dramatic decrease in growth. Try upping your GFO a bit to knock it down to 0.03-0.08ppm. How are you adding your cal and alk supplement? If your adding "a lot" like you said it may be that your adding them to close together and they are precipitating out. Also how stable are your parameters. Stability is more important than hitting target numbers.
 

brad

New member
.12 is on the high side but it wouldn't cause a dramatic decrease in growth. Try upping your GFO a bit to knock it down to 0.03-0.08ppm.

Not using GFO, but if you read my latest post, I have no measurable phosphate.

How are you adding your cal and alk supplement? If your adding "a lot" like you said it may be that your adding them to close together and they are precipitating out.

The plan is to eventually constant drip Randy's 2 part into my sump, or go back to a calcium reactor. Since I had a crash, this is basically a brand new 300 gallon system with a few tiny frags, so I didn't think I'd have to worry about Ca or Alk until something started to grow. I measured the first time 1 month ago to see if this is why nothing was growing, and was shocked when I saw about 300ppm Ca and 6 dKH. I fast-dripped 2 part 1 part at a time to get things back where they are now. I know levels are not falling from adding things too close together, since levels fall fast even after a few days of not adding anything. I did pick up a HUGE squamosa and I suspect it is the reason levels are falling, but am still surprised 1 clam can make such a big difference in such a big tank.

Also how stable are your parameters. Stability is more important than hitting target numbers.

System is not stable at all. Maybe that is the problem.
 

dunc101

New member
Just as an FYI, Red Sea's program recommends a PO4 level of .1 if you are going for fast growth and .03 if you are going for colorful corals with a bit slower growth. The major difference is at a higher level of PO4, you will have more browning out of the corals b/c of more zooxanthellae. To high, however, and it will start to inhibit growth. The main difference I have found is that at a higher PO4 level, you start to get some nuisance algae growth. If your tank is not stable as you suggested above, I would think that is your entire problem with growth. Until my ALK levels remained pretty much constant, I received poor growth with my SPS.
 

animalkingdom

New member
ive had growth slow down with higher phosphates before, but as it seems you have figured out the thing that slows growth for me the most is instability, specifically when I forget to fill 2 part reservoirs and they are empty a day or two. the low calc and alk set me back a few weeks to a month on growth even though the levels were only low a few days.
 

Constrictor6090

New member
Use Red Sea Coral Pro Salt and you will see coralline algae grow like algae is suppose to. Clams take up a Lot of calcium, that's most likely where it's going unless it's building up in the PVC or pumps. Definitely do water changes. It does a lot more than people sometimes think it does.
 

ampemployee1

New member
You didn't mention anything about what you feed your corals. I had relied on fish poop, but started oyster feast, and growth has improved considerably.
 

Constrictor6090

New member
It's a 650g system, and I only have 5 fish in it, flake food is fed once a day. Other wise I do 10% wc every week w/ RSCP and dose b-ionic.
 

brad

New member
You didn't mention anything about what you feed your corals. I had relied on fish poop, but started oyster feast, and growth has improved considerably.

I am not feeding my corals. However I did not fed them before the crash either.
 

acabgd

New member
Do you check your Mag at all? There is a correlation between Alk + Ca + Mg which might be the reason you must dose high amounts of Ca without much improvement.
 

brad

New member
Do you check your Mag at all? There is a correlation between Alk + Ca + Mg which might be the reason you must dose high amounts of Ca without much improvement.

Not yet, I may pick up a Mg test kit, but would be very surprised to see anything more than a few percent different than freshly mixed Instant Ocean.

While this would affect how much I need to dose, I doubt it would affect growth.
 
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