This doesn't appear to be a simple case, so I will run down every possibility I can think of, no matter how remote.
2. distance is about 20 inches
3. Photoperiod is 10am till 7pm, 9 hrs thought it was 8.
I've never used and am not terribly familiar with PC lighting, so I had to look up a few things.
First, from this thread
, I see that a single 36W AHS PC light gives about 40 PAR at 20" from the substrate.
A 55W PC is longer, so the PAR at the substrate should be virtually the same. Given your tank dimensions of 30-1/4" x 12-1/2" x 22-3/4", and that you have two PC lights, you probably have them in this orientation, side-by-side:
Which doubles your PAR to 80, the lower threshold of high light.
A nine hour photoperiod isn't excessive, and barring any unusual PC quirks I may be unfamiliar with, neither is your intensity; but as GSA/GDA on the glass can be a symptom of excessive intensity or photoperiod, I'd suggest going ahead and bumping it down to eight.
1. Im using 4dkh solution
Great. Between this, yellow-green drop checker color, and your pH controller, I think we can disqualify CO2 as an issue.
You're using EI dosing for 20-40G high light and heavily planted tanks, plus some extra iron. This should be more than enough macros/micros to disqualify any deficiencies in these nutrients.
Given your tapwater parameters of 12°KH and 10°GH, and after dilution with RO water down to 7°KH, there should be plenty of GH left. However, we don't know what that GH is from. Normally I'd expect a healthy ratio of calcium and magnesium, but it would be nice to know for sure. Can you get a water report from your city that lists this?
Tapwater so high in mineral content may also contain high levels of other things, like phosphate. I've seen enough reports from people who had high tapwater phosphate levels to believe that in some cases, it acts quite differently than the phosphate we dose, inducing algae whereas KH2P04 will not. Have you tested your tapwater for phosphate? Since you already have an RO unit, it might be a worthwhile experiment to try doing water changes with it alone, using a GH Booster to bring your GH back up.
4. Fish is angel fish, siemese algae eater and a few ottos not sure how many only see them once in a blue moon.
Only the angel fish worth considering here. If you have a lot of them and they're fed heavily, then in combination with dosing EI for a heavily planted tank when it's only moderately planted, you may have excessive nitrates. I ran into this problem, at 140ppm nitrates I had symptoms of insufficient phosphates (despite them being at 30ppm), uncontrollable GSA/GDA, and plant stunting. If you believe this is a possibility, a nitrate test may be in order.
5. I'll get a picture of the black algae tomorrow when I can get a camera.
A nice little potpourri of algae.
A full tank shot would be beneficial too, so we can see the extent and locations, which may reveal additional possibilities.
Some of this looks quite unusual, and I suspect a lot of it is in part BGA. It comes in a variety of forms and colors, not just the most commonly encountered blue-green. And it can form symbiotic relationships with various algae, which can further change its appearance, or even totally mask it. Symbiosis with GDA is fairly well documented, and if BGA is involved, killing it alone leads to the decline of the GDA. BGA is also notorious for altering its own environment to make it hospitable to algae, regardless of your attempts to correct it. I would suggest a thorough manual cleanup to remove as much algae as you can, followed by treatment with erythromycin.