How are these numbers?

[hkgar]

I was trying to maintain a ULNS but I am a heavy feeder and even using a ATS, skimmer and dosing 32ml of 50/50 vodka/vinegar my 3's are:
Nitrate 8
Phosphate .04

Calcium 450
Alkalinity 8.0
Mag. 1350

My growth has slowed. I (not me, my tank) was using about 2 dKH per day but I am down to less than 1.

Lighting is 2 250 W Radiums and 4 80 W T5 (ATI 3 Coral + and 1 Actinic)

7 hours MH
11.5 hours T5

In June I switched to all (8) t5 for the summer as I did last year - with no ill effects, but wit the reduced nutrient uptake, I switched back to the above. Temp ranges from 79 to 83 with the MH in the summer. I was switching to keep the tank cooler. With 8 t5's it gets to about 81.

[bif24701]

Seem fine. Good work


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[jda]

How old is your tank? If you have a sand bed and/or used real live rock (not dead, dry or man-made), then your nitrates will eventually get to zero as the anoxic bacterial zones get established, but this can take a year, or more.

I am a LNS guy, but ULNS benefits do not outweigh the risks, IMO. I like to be at .005 P and .01 N... or near NSW levels.

Turn a fan on over the top of your tank with the same timer than turns the lights on. I just use a Vornado from Home Depot or Lowes.

[hkgar]

jda, thanks for your comments, but...

This tank has been up for about 4-5 years (I lose track). A quick look and you would see my join date for RC is Oct 2002 and have 3530+ posts. I have a sand bed of varying depths fro 1/2 to 2 inches.

I do have two fans in the canopy controlled by Apex (as are the lights and many, many other things.

My overall question is why has the growth rate (based on dKH consumption) dropped 50% or more?

[jda]

You need to get the temp swing down. Do you turn the fans on with the lights, or with tank temp? Turn them on with the lights... and not just computer fans, use a real fan or fans. I have no idea how you manage this or what your setup is, but in Missouri with 100+ degree days and 80%+ humidity, a simple $20 Home Depot fan on the same light timer with open hood doors could keep me to about a 1 degree temp swing with nearly the same lights.

For optimum growth, your N and P are going to have to go down - 8 and .04 can grow coral, but not as fast as they can. Calcification happens when P is very low... like NSW low. Your tank should be able to handle nitrate, but perhaps the sand is not deep enough - I have no idea about this.

Your post started with "was trying" so what were your parameters before when the growth was better. Probably one thing was temp since it was probably not summer. What was the rest of the old plan?

I have been here nearly as long with 5K+ posts and I have a tank that is less than a year old. :)

[hkgar]

The fans are not computer fans but they are only 4 inch fans purchased a Walmart type store. I will check Home Depot for larger fans. They fans turn on basically when the lights do If Tmp > 79.0 Then ON, The heaters are set to on at >78.5. I will change the fan to on with lights.

I was previously keeping NO$ at 0 and PO4 <.02. When I did this I was maintaining dKH at 7.5-7.8. I have not increased my carbon dose amount and was resetting dKH at 8.0 with the higher nutrient levels.

I think I will go back to 0 and <2. I feed very heavy (the herbivores get 1/2 sheet of nori and I feed 9 grams of homemade frozen).

I am currently dosing a 50/50 vodka/vinegar mix at he vinegar equivalent rate of 132ml. I will gradually push that up till NO3 hits 0, and drop the dKH.

[bif24701]

You need to get the temp swing down. Do you turn the fans on with the lights, or with tank temp? Turn them on with the lights... and not just computer fans, use a real fan or fans. I have no idea how you manage this or what your setup is, but in Missouri with 100+ degree days and 80%+ humidity, a simple $20 Home Depot fan on the same light timer with open hood doors could keep me to about a 1 degree temp swing with nearly the same lights.

For optimum growth, your N and P are going to have to go down - 8 and .04 can grow coral, but not as fast as they can. Calcification happens when P is very low... like NSW low. Your tank should be able to handle nitrate, but perhaps the sand is not deep enough - I have no idea about this.

Your post started with "was trying" so what were your parameters before when the growth was better. Probably one thing was temp since it was probably not summer. What was the rest of the old plan?

I have been here nearly as long with 5K+ posts and I have a tank that is less than a year old. :)



My temp swings +/- 1-2 degrees and my NO3 is +5ppm, PO4 .05. I've got no problem with growth in fact it's increased this summer and with adding nitrate to my system.


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