Need advice on lighting a 55 re ODNO

[Dave J]

At present I have a 55gal tank that is in a one piece cabinet that has
47" clearance end to end.A full 4 foot tube with endcaps will not fit. I am currently running two URI aquasun 46 1/2" bulbs for a total of 220W.
I am not all that happy with the results, I get decent growth but at present no pearling. When I do a water change I notice a bit of pearling but that is when the water is at half depth.
I have done a fair bit of reading on the ODND setup and was wondering if you think I would be better of changing over?
If I do change do you think I should change what would be my best bet for bulbs? 36"?? or??
Just remember a full four foot bulb will not fit into my setup.
My Parameters are KH=4 GH=8, CO2 with a controller PH 6.8, 12 hour photo-period, dose TMG, K, FE, KH2PO4, Magnesium Sulfate,Potassium nitrate( all according to Chuck Gadds calculator)

[GulfCoastAquarian]

First let me say that you have a beautiful tank.

You'd have to run three ODNO lights to match the light your VHO URI aquasuns are making. Four would make for a slight improvement. I think your lighting is excellent as it is. What ballast is running your aquasuns? Icecap 660?

Your CO2 is around 20-25ppm right now, with your KH at 4 and pH at 6.8. You're getting good growth, but I still think CO2 is your limiting factor. And there are usually some acids other than carbonic present in the water that skew your pH a bit lower so your CO2 levels could be as low as 15-20, which is not at all optimal for 4 watts per gallon. Set your pH controller to 6.6 for a few days and see if the plants don't pearl by mid-late evening. They should, with your setup.

But once again, I definitely wouldn't recommend ODNO lighting to replace your VHO's. If you're using a good ballast, those aquasuns should provide far more than enough light for your tank.

[Dave J]

Yes I am using the icecap 660.
I was more worried with the quality of light.
I still have some 50/50 bulbs from when I had a reef.
Do you think one of each would make a difference?
or should I stick with the two aquasuns?

[GulfCoastAquarian]

It's always worth experimenting with the 50/50's for a day, but my guess is that the aquasuns produce more light in the spectrum that plants thrive in. The 50/50's are likely to not produce enough in the red spectrum.

[Dave J]

Thanks for your advice.
Just did a water change and turned the controller down to 6.6
Will try that for a couple of days, see how it works.

[Rex Grigg]

A 55 with 220 watts. What is your fertilizer schedule? What are you using? I have 220 watts of AH Supply lighting over my 55 and get awesome pearling, if I keep the plants fed. If you were going to change your lighting I would look at the AH Supply kits. The reflectors they have are awesome. You can have all the light in the world but you need to get it into the tank.

[Dave J]

As to reflectors I have a full reflector setup behind the bulbs, sort of similar profile as the Spyder light reflectors if you are familiar with those.
Highly polished surface, full length of the tubes.

I dose daily.
5ml. TMG
Fe 5ml (every other day)
And then all according to Chuck Gadds calculator
Magnesium Sulphate
Potassium Nitrate
KH2PO4
K2SO4
All of the above from a hydroponic store

I now do a weekly 50% water change, but up till now it was more like every 2 to 3 weeks.

Rex as you can see I also have a problem with some heavy green spot algae.

Here is a picture of my GS algae

Here is my tank as of today after some major reovation

[GulfCoastAquarian]

Something is definitely amiss. How old are the bulbs? Try switching to the 50/50's and see how they respond. I can't see anything wrong with your fertilizer schedule. Have you seen any pearling with the increased CO2 levels?

[Dave J]

One of the bulbs is almost a year old but the other is brand new.
I have noticed a slight increase but I actualy have to turn off the pump to see any pearling. I just checked my KH and it is at 3 so I just added some sodium bicarb. to bring it up to 4.
Still confused as to what it might be that is out of whack.
Ph controller was calibrated Dec 22. Maybe I should do it again?

[GulfCoastAquarian]

Can't hurt to re-calibrate. What did you mean when you said you had to turn off the pump to see pearling? You mean you had to turn off your filter to eliminate circulation? Could it be you're seeing surface agitation? Sorry I'm just stabbing at guesses here.

[Dave J]

Let me start by saying thanks for all your help.
What I meant about tuning off the pump is that with the water circulating in the tank, I couldn't see any oxygen bubbles at all coming off the plants.
But when I tuned off the pump( a Hydrothruster (500 gal/ hour), with 6 feet of head out of my sump.) Then I was able to see the odd very fine bubble from the plants , but only when the water was dead still.
But I have to let you know your trick of dropping the controller has worked like a charm, my glossostigma is bubbling like crazy now and things seem to be working great. Earlier this week I think that my KH was a little low after my water change and once I got it back up to snuff, I was off to the races.
But I think the best thing was that I dropped the controller down to 6.6 as you suggested.
Again I thank you for your help and advice
Dave

[GulfCoastAquarian]

Glad things are looking good. That's a good pH level to keep most fish. If you don't like it, you can raise your KH some more and set it back to 6.8 and your CO2 levels should be high enough to where you want it.