Advise on MH hanging height

[o2bubble]

Hi bros, I bought 2 x pendant-like MH set (150w) and wondering whats the best height to hang above the water surface? Read ADA's recomendation 30-50 cm depending on the plants (fast or slow growing). Mine is fast growing (rotalas behind and sides and tenellus in centre) except crypt and nana at the sides.

My tank is 4x1.5x2 ft, any advise from experienced bros here? Should I start with 30 cm first? Thanks so much!

[medicineman]

I believe at 4 feet of length, the coverage even at less than 30cm high is already very well.

However as a multiple MH user I do agree that MH should be hanged at least 30cm high as setting it too low will only cause more trouble that what you want. Burnt plant, too intense than you need, more heat transfer, more algae issue.

You can even do well on 70W ones over this tank if you do not really need very intense light over your setup.

[o2bubble]

Thanks bro, already brought the lights and ada bulbs.. can't change to 70w now. I will give it a try at 30 cm first. Hope the results will not be bad...