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Large 225 Gallon New Tank ~ 3x 250w MH Ok?

1256 Views 8 Replies 5 Participants Last post by  captain_bu
Hello all,
I am new to freshwater planted tanks. I have had regular freashwater fish only tanks and saltwater setups, but never a dedicated planted tank. This is my first post so I just wanted to know if I could use my saltwater light setup for a planted tank? Here are my specs:

225 gallon 72"L x 24"W x 30"H
3 x 250 watt metal halide setup ~ needs new bulbs

My main concern is the depth being 30 inches.

Would this lighting setup be sufficient for most aquatic plants? I don't know the names about specific types of plants but I really would like to get a "grass like" effect or perhaps baby tears to form a compete Matt covering the substrate with possibly a few larger plants in the background.

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You don't need to worry about having too little light with that setup.

FW planted tanks don't need nearly as much light as SW reefs. I don't know much at all about MH, but it will probably even be too bright. Are you planning to get a pressurized CO2 system?

4x T5HO bulbs (or 8 total, because it's a 6 foot tank and you would need two 36" fixtures) would be a good amount of light for most plants on that tank. Compare that to what you would use on a reef.
A good general rule is that any lighting that is good on a reef tank is too much for a planted tank. Our tanks are very, very dim compared to most reef tanks. But, after you get used to it, they look plenty bright.
So would 3x250w MHs be harmful? What if I cut it back to only 2x 250w MHs?
Keep in mind it is a 30" deep tank

If you look at the chart in this post:

you will see that HQI (MH lights) at your depth would be off the chart for the amount of light your tank needs. You will burn your plants. If it were me. Do to the depth and width I would go an 8 light fixture and rewire it so you are only using half the ballasts which the active lights being every other one. But that's only if you want to run high light. Which will then require you fertilize and run CO2.

Reason I suggest the 8 light is the body is wider, give you better spread.

Or you can also run two 2 bulb fixtures mounted spaced apart for a total of 4 bulbs. Might be cheaper!

These guys listed below will make lights to order depending on your needs. great prices. I paid $150 for a 7 ft light with two 48" T5HO lights, german polished aluminum and a wide 7" body which is meant for 4 bulbs to help with light spread.
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He didn't list the wattage for the HQI he tested and said that because he only tested one fixture, it shouldn't be used as a guide for HQI only as a reference compared to the fluorescents.
250 is the midpoint and considering it's considerably stronger than the best t5 I would assume it would be safe to assume regardless the HQI will be stronger.

sure e can use them but they might end up having to be 2 ft above the tank to control algae or be only to run the lights for 5-6hours tops. I know in reed systems people run their lights for like 11 hours with only 5-6 of that being HQI and the rest other lighting.
The other reason for not using insane levels of light on a tank this size is that it will not only require CO2 but be harder to maintain adequate levels throughout the tank. You will need really good CO2 circulation. Less light means lower CO2 demand to be met.

Agree that 4 T5HO bulbs will be more than enough. Also suggest calling Catalina and having them build you a four bulb T5HO fixture with a nice wide housing.
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