I need some help here, if toms around or someone who has some good advice Id appreciate it. I recently changed the lighting over my 29 gallon hi tech tank from a 65x2 coralife PC fixture + a 20x2 t12 fixture to a single 150watt Metal halide (the fishneedit.com one with their 8000k bulb). As I expected I just had a major aglae explosion of BBA. I am running the halide about 10 inches above the tank for 5.5 hours a day. My co2 seems fine with a drop checker, although Ive been continually easing it up and keeping an eye on the fish. Tank was fine then I noticed a little bit of it which I think came in on another plant, I changed some water, removed some and all was well for a few days. Then I missed 2 days of dosing, and all hell broke loose. I think maybe Im dosing too lean to begin with. I think I may have nitrates in my tap water as test always show them present so I dose 1/8tsp 2x, 1/16tsp 2x P, 1/8 tsp 3x K, 4ml flourish 3x, 1-2ml Kent Iron 3x all weekly. I also add 2ppm of MG and 7ppm Ca at water changes which are 40% every 5-7 days. Im assuming I should have upped my dosing with the addition of the higher lighting but assumed I was already in excess. My tank is pretty well planted but I dont have a ton of fast growers. I have bacopa C (about a 12 stem bunch 12" high), about 12 stems of L. Aromatica about 10" high, a nice size bunch of narrow Java, 2 anubais nanas, 4 buches of blyxaj, and about 10 small 3 or 4 stems bunches of dwarf lobelia. A decent amount of plants but not alot of fast growing nutrient suckers, like rotala, and ludwigias wtc. I am going to try some flourish excel, I already pumped up the co2 some, Im going to drop the lighting period to 4hours daily, and am waiting to hear from someone here as to if I should up my dosing (Im assuming I am). Some of my plants are almost totally covered. Should I just toss them and add more fast growers as well? Or will the excel clear them of the BBA? Any advice here will be greatly appreciated. And no Im not ditching the halide, Im not a newbie, just trying to get this right. I dont care how much work it is. thanks.

Are you using 4KH distilled water in your drop checker? The reason I ask is that co2 fluctuations are a major cause of bba as you probably are aware.

I think you could easily double that dosing as long as you're doing your weekly water changes. It seems pretty lean for the lighting you have now.

Make sure you vac your gravel on every water change.

Prune all plants that are affected with bba. If a plant is really infested, do a bleach dip 1:20 for 3 - 5 minutes (3 for more delicate plants). This will kill it. All bba has to either be removed physically, or killed. It doesn't just die off, unfortunately. It just stops spreading.

I wouldn't reduce your photoperiod that much. When dealing with algae it's usually better to reduce intensity if you have to reduce something, unless you are doing more than a 10 hour photoperiod to start with.

Manual removal, water change, dose (increase co2); repeat as needed until gone.

So you are at 5 wpg for a 30 gal tank? I know you had this before but MH light is much stronger and more focused, not spread as well. Keep this in mind.

You have really increased the demand for nutrients by this switch.

I would definitely ensure you have the 4kh water in your drop checker as Carissa said, and that the color is green. move it around daily to different parts of the tank to be sure of your flow.

If you can, raise the lights higher. A MH is very bright. I went from normal floro tubes to MH, and the difference is unreal.

You can always lower it if you need more. I think now you have too much.

I would also think that an increase in c02 and dosing would be in order......start out small and go from there....

I had good luck with the 3 day blackout with daily 50% wc and excel. Pruned aggresively, used only nice cuttings etc.

The blackout and the manual cleaning will help get you to a better starting point. Then adjust from there..

Hope this helps.

FYI.

I just tried the dip Carissa suggested and it is working wonderfully.

I had been reluctant to try it.

I dipped my P. Stellata stems for 3 min as the plant had been infested with diatoms and different algae.

Then rinsed in bucket of clean water, then tank water (bucket), then in tank.

What a difference!

Now I can see what I need to prune.

Am dipping my bolbitus, anubias, and java fern next.....

Thanks so much!

Rinsing in heavily dechlorinated water also helps remove any bleach residue. I just add a capful to a small bucket of water and use it for rinsing. If something is heavily infested, swishing it around while it's in the bleach and in the rinse water after will cause some of it to actually come loose and fall off. This worked well on my java fern which was so lush I couldn't possibly prune or pick it off.

When it comes to most any algae, manual removal can't be overemphasized. It's the course of least resistance to want to be able to just add 'something' to the water and have it magically all fall off and die, but it rarely ever works that way. BBA especially, since almost nothing will eat it either. A bit of elbow grease spent removing algae after it first strikes usually works much better than waiting around to see if it will die, and ending up with 10x as much work after it spreads to the point of no return. There are two steps to fixing an algae problem, one being fixing the problem that caused it in the first place, but the other being removing everything that is in there afterward.

FYI, most of my stellata has melted along with my beautiful Cabomba and Lobelia.... Only things doing well are the Windelov and Anubias......

My ludwigia sp may pull through, but they are melting as well, just not as quickly.

The lobelia was gone in 2 days, and the cabomba tips are ugly!

I hope that some of it will regrow, but looks bad right now fer sure..........

I didn't think I even had 1:30 and I only soaked for <3 minutes (well I think anyway).

I assume that I soaked them too long or had too strong a solution........

So, I think maybe the more delicate guys should get a 20-30 second dip/shake next time, to see if this lessens the adverse impact...

Looked good that day, but the next morning woke up and stellata leaves were covering the surface like duckweed Been downhill ever since..........

The stellata look like native palm trees in that I have a nice thick main stalk, but nothing on it! Looks pretty sad.....

Anyhoo, just a caution when using this method.......