10k to 20k ??


New member
I have a 36” Current USA, Outer orbit light with 2, 150w 10k and 4, 39w Actinic’s. I like the light a lot but after seeing the clarity of 20k bulbs, I need to upgrade.

Questions â€"œ (sorry, know nothing about lights yet)

1, Can I simply replace the 2 150w 10k bulbs with 2 150w 20k bulbs?
I can’t find a 150w 20k bulb and it makes me wonder if they exist.

2, If I upgrade to 2 250w 20k bulbs can my ballast handle it?

3, I read that Ushio is the best as far as replacement bulbs, is this correct?



Premium Member
1) Yes, it won't be an issue as long as the watts are the same.
Click here there are a couple of 20K 150 bulbs.

2) Would need a 250W ballast and the mounts might be a different size.


New member
The Current USA 150 watt HQI fixture will accept 250 watt HQI but you need to buy the two 250 watt reflectors from Current USA and two 250 watt sockets which you can also get from Current USA cheaper than anywhere else. The 250 watt and 150 watt reflectors are cut differently for the different sockets. You would also need to purchase two 250 watt ballasts. The ARO or old style Ice Cap 250 watt electronic ballasts can be retrofit into the Current USA Fixture. It's a bit of work and will cost you about 270 dollars in parts alone, not including new bulbs.

Staying with the dual 150 watt is the easiest bet and they do have 150 watt DE 20000K bulbs. You could be giving up quite a bit of par by changing to 20000K from 10000K.

Ushio isnt necessarily the best replacement bulbs you can get. There are alot of good ones available. But Ushio does make some good ones. If you are just looking for a bluer look, maybe the Phoenix 14000K would be a better bet. It's pretty blue and has better par than most bulbs that are as blue or bluer than it is.


New member
My 10k seems to give everything a brownish color. Actually, I like the look of my tank when only the actinics are on.

What's the impact of less par?

Would you describe the 20k as giving a blue color? Is that why it looks so clear?