Growth.

[RJKain-777]

Hey every one, I’m having a slow down in growth, I had an explosion of coralline about 3 weeks ago, and since then everything kind of stopped.

My Alk, calcium, magnesium and nutrients have all been stable at these numbers:

Alk 8.5
Calcium 440
Magnesium 1350
Nitrates 2ppm
Phosphates 0.08 ppm.

All tested on a Hannah checker except the magnesium and I traces which I’m using salifert.

I’m dosing acropower at 2 ml a day as well as feeding PE mysis and calanarus daily.

I do bi weekly water changes of 10 gallons using Red Sea blue bucket. .


I’m wondering if I bump up my Alk to 9.5 if I’d notice a bit more growth?

This birds nest was my fastest grower, these 2 photos are 2 months apart.

 

[Tuan’s Reef]

Alk consumption slowed ? Your corals look great! I wouldn’t do anything and monitor

 

[Tuan’s Reef]

On a side note tho... I have noticed an increased to growth, ph , calcium , mag, and Alk consumption when I bumped my Alk to 9.5 from 8.5 dkh

 

[RJKain-777]

On a side note tho... I have noticed an increased to growth, ph , calcium , mag, and Alk consumption when I bumped my Alk to 9.5 from 8.5 dkh

Nothings changed, Alk is and has been stable at 8.5 since I set the tank up in August. Lol

I’m gunna bump it up a bit today.

 

[McDam]

Be very careful bumping up alkalinity, you will want to do it over a few days to even a few weeks. The slower the better.
If you do it too quickly things may seem fine for a while but then in a few weeks to a month the corals will start rtn'ing or you will notice bleached tips and be scratching your head as to what the cause is as everything seems stable.

 

[The Aquatic Arsenal]

Do everything nice and slow, which I am sure you already know lol

 

[RJKain-777]

I’ll bump it up over the next month.

Just tested my phosphates and they’ve raised since last time, that may have a part in it

 

[Dkeller_nc]

I'd be extremely cautious interpreting that your growth has slowed down due in part or whole to a (slightly) elevated phosphate concentration. There are lots of tanks with considerably higher phosphate concentration than you've noted with very fast SPS growth.

I mention that simply because you've considered increasing the alkalinity while also noting an increased phosphate concentration. The general rule is that high alkalinity and low dissolved inorganic nutrients tends to cause "burned" tips, and sometimes RTN. So it may be a bad idea to add a phosphate reduction material such as GFO to your tank and raise the alkalinity.

Another thought is that corals use other inorganic trace elements other than the "big three". There's no way to know without testing, but it may be that your corals did an effective job of utilizing these trace elements, and your feeding and water changes haven't been enough to replenish them. So your growth slowed somewhat in response. That doesn't mean, btw, that I'd recommend adding a trace element mixture. Doing so can be effective, but it must be done very carefully, since there's a range where certain trace elements are necessary for growth/health, and a concentration above that range where the particular element or compound is toxic. Potassium is a good example.

Perhaps a safer way to ensure that you're not trace element limited would be to up the frequency or amount of your water changes, or both. You mention 10 gallon water changes, but don't note how big the tank is. Recommendations vary, but a lot of folks follow about a 20% change every 2 weeks for this very reason.

 

[RJKain-777]

I'd be extremely cautious interpreting that your growth has slowed down due in part or whole to a (slightly) elevated phosphate concentration. There are lots of tanks with considerably higher phosphate concentration than you've noted with very fast SPS growth.

I mention that simply because you've considered increasing the alkalinity while also noting an increased phosphate concentration. The general rule is that high alkalinity and low dissolved inorganic nutrients tends to cause "burned" tips, and sometimes RTN. So it may be a bad idea to add a phosphate reduction material such as GFO to your tank and raise the alkalinity.

Another thought is that corals use other inorganic trace elements other than the "big three". There's no way to know without testing, but it may be that your corals did an effective job of utilizing these trace elements, and your feeding and water changes haven't been enough to replenish them. So your growth slowed somewhat in response. That doesn't mean, btw, that I'd recommend adding a trace element mixture. Doing so can be effective, but it must be done very carefully, since there's a range where certain trace elements are necessary for growth/health, and a concentration above that range where the particular element or compound is toxic. Potassium is a good example.

Perhaps a safer way to ensure that you're not trace element limited would be to up the frequency or amount of your water changes, or both. You mention 10 gallon water changes, but don't note how big the tank is. Recommendations vary, but a lot of folks follow about a 20% change every 2 weeks for this very reason.

Tanks a Red Sea 425, so 90 gallons. And I never stated in my second post how high they raised over a little while. It’s now 0.30

 

[Dkeller_nc]

Opinions on optimal phosphate levels vary quite a bit. Personally, I want phosphate levels somewhere in the 100 ppb - 500 ppb range (and nitrates around 10 ppm). Others sometimes want them as low as 50 ppb.

But the bottom line does seem to be that really low inorganic nutrients (PO4 & NO3) and high alkalinity (>9 dKH) doesn't seem to work out well. There are, however, some exceptions that I've seen where folks are heavily feeding zooplankton coral foods but nevertheless maintaining ultra-low-nutrient-systems (ULNS) and relatively high alkalinity. The particular tank that I'm thinking of was setup with an autofeeder to dispense Reef Roids 4 times a day, with an automated roller mat to remove uneaten material quickly.

Based on the details that you've posted, I'd suggest upping your water change amount to 20 gallons, and perhaps do it every week for a month, then observe the results. That will have the effect of helping replenish any trace elements, and it will also (probably) drop your phosphate concentration in a slow, controlled manner.