According to a mix of the T5 chart on this link and a bit of "figuring"... because the two bulb fixture is not on there and you need to read the "Low, Med, High light" part which list the numbers for each category.
I will venture a guess @ 65-75 PAR @ 20"(notice I'm giving myself a rather large window) which is IMO at the very bottom of the high level.
The high level almost has no top end(250 is the highest I've seen listed) while the med level is only 15 from bottom to top 35-50 so IMO the top of med should be near 65-75.
But then it's just my opinion on that part.
Your bulb set up is identicle to mine but I just use the True Lumen 6700 "Flora" bulb
and I use the aquaticlife Roseated 650nm bulb. That True Lumen Flora is awesome for natural looking color in the tank without glair. Don't understand how any bulb can be that much better than other brands of bulbs and not be know by everyone by word of mouth.
I have a different brand of fixture @ 12" above and that chart doesn't list what the level would be under 15" at which it says 100 PAR(guess they didn't think anyone would be dumb enough to put a dual bulb T5 in a 10g tank) and (no-really) I do have algae. I use my own version of EI/low light weekly(reduced level) and Excel @ 2x recommended doses.
I might suggest you put one or two in each end in front of the heaters(don't mix just put one kind in each corner) a water Sprite and a water Wisteria. Or you might try this in one end as it gets fairly big.
And there appears to be two cavities in the left piece of wood(dark places in the picture) and a piece of this in the top one would slowly spread.
And BTW a Crypt Wendtii "Bronz" would give it a different color without turning it into a circus of red.