Metal Halid for freshwater?

[JustinKScott]

They are hot and expensive initially (unless you scour CL). But a metal Halid should work for a freshwater planted, right?

My question is how do I know how many & how many watts?

I have a 180gallon (681 liter) tank that is two feet deep. Id like to grow large leafy greens & make it pretty dense.

I've seen CL deals for ballasts for two 175w for less than $100 and 6700k bulbs from eBay for $20ea. Is that enough lighting?

How would I be sure it's enough before I buy?

 

[mfdrookie516]

They are ok for plants, but they cost so much more, both in bulbs and in electric usage. IMO, you'd be better off going with T5HO's.

 

[JustinKScott]

I have 6 already. Don't seem to be enough. 24" is very deep.

 

[mfdrookie516]

Depth doesn't play a big part. I've read too much online that contradicts the typical "the deeper the tank, the more light you need" theory. I have 8 24w T5HO's on my 125 (which your tank is only 2" deeper) and my plants are growing exceptionally well... even my carpet plants are carpeting rather than being laggy.

 

[BigJim]

I'd also stick with the T5HOs or go with LED instead of MH.

 

[JustinKScott]

Ok ok ok. That's what everyone except the LFS is telling me; big Jim has told me the same thing like three times.

The plants are green and seem to be getting taller, but really slow and they have unsightly algae on their leaves.

I've not grown plants before. Maybe I have unrealistic expectations about how fast the plants should be growing; how "fast" is a "fast plant"?

I have ottos, sae, and a bristlenose; one liter of working diy co2; floramax & play sand, and no ferts.

 

[mfdrookie516]

My guess is you have algae because of the DIY Co2. There's no way a one liter bottle is going to provide enough co2 for a 180g tank. And, just a little co2 is worse than no co2. Once you find the balance between lighting, co2, and ferts... your plants are going to grow extremely fast.

 

[JustinKScott]

I was reading on plant geek last night. Seems like I have green spot algae. He says it's most commonly from high light. So looks like +1 for no need for metal halide. If I had bought the mh lights, I guess my problem would have only gotten worse.

I've been running co2 for only 3days now, but the plants & algae has been around for a months; so I doubt it's because of co2. Only now am I seeing some improvement; so I think the co2 is helping.

Why only one liter?
I tried pop bottles and milk jugs both were hard to sea and way too hard to keep sealed. I finally tried a tequila bottle with a thick wooden/plastic cap. Perfect! So I now just need to drink 3 more bottles!

I think instead of spending $150 on halides; I'll buy root tab ferts. What do you recommend and from what store? Jungle labs is the only kind I've really seen locally.

 

[mfdrookie516]

The reason I made mention of the co2 is because even if you don't have problems now, you probably will. DIY co2 tends to fluctuate. Also, for a tank of that size, one generator is not going to be sufficient. Without getting your tank above 30ppm co2, BBA is going to love you. It absolutely thrives in co2 levels above equilibrium (7ppm?) and below 30ppm. I started running my tank between 35 and 40ppm co2 and my massive outbreak of Co2 has finally subsided.

I'd suggest spending that $150 on a pressurized co2 setup. That'll get you almost everything needed. But, if you're not wanting to go with that, I wont push you. I really thing no co2 would be better than DIY (at least your current setup) on this tank though.

 

[fort384]

I tend to agree... your slow growth and algae issues are caused by a lack of something... but probably not light. I also agree that a pressurized CO2 system is the only way to go. Running DIY on a 180g tank is going to be an exercise in futility. I doubt it will even raise the co2 enough to cause BBA issues. A single generator probably won't raise the tank much above equilibrium.

 

[JustinKScott]

Don't know if many respond with their success stories; but I'll at least give an update.

I read on the internet somewhere that plants like nitrates around 20-30. So I thought I'd give it a try. I let the tank go a little longer between water changes & got it averaging around 30ppm.

A few interesting things have happened in the last few days.
1 my phosphates dropped
2 New leaves are forming
3 Many of my plants are not looking sickly anymore
4 my herd of algea eaters seem to be winning a few battles
5 The clover looking plant (forgot the name no, because i thought it was dead) which I buried all over my tank is starting to pop little "clover" heads.

Don't know if the co2, nitrates, or the selling my 4 angels did it... But those are the only things that changed.

Don't think I've quite won the war; but for once, the future is not looking quite so dim for my plants.

 

[fort384]

Great! Your PO4 dropped because your plants are no longer N limited, so they are utilizing both N and P now. Sounds like you are close to a balance.