Help Me Get To High Light

[rcherry]

I'm fishless cycling a 75 gallon tank with a 20 gallon sump. I'm looking to eventually be able to grow pretty much whatever I want in the DT. I plan on getting CO2 set up in early-mid June, and I plan on dosing ferts with the EI method. I'm pretty sure I'm going to go with T5HO, as it seems to be the most cost efficient method. My question is how much lighting do I need to get to high light? The other problem is I don't want to have high light before I get the CO2 going, I'd rather not fight a losing battle to algae. I was thinking of getting a 2 bulb 48" T5HO fixture this weekend, and then eventually adding a second when I get the CO2. Does this seem like a feasible plan?

I also have 2 10W screw in CFL bulbs over the refugium of my sump. Where does this light put me? I'd like to be able to have some plants going down there as I would like to have some inverts and in the future some fry growing out down there.

Thanks for all the help. I posted a question similar to this in the past but I want to double check as I plan on ordering that 2 bulb T5HO later today or tomorrow and want to make sure I'm not throwing my money away.

 

[BillD]

You can temporarily lower your light intensity by raising the light above the tank.

 

[mfdrookie516]

I think a 4x54w T5HO would be best from the start. Most fixtures allow you to run 2 bulbs at a time. 2x54w wouldn't require co2, but would be a good amount of light to get started. 3x54w would probably be sufficient, so it would be up to you whether you want to keep it 3x54w with one actinic, or 4x54w... once you get co2 set up.

For a good affordable fixture, check out fishneedit.com. I have 4 fixtures from there and love them. The remote ballast is something I really like about the design, as well as the cost, the good reflectors, and the slim design.

 

[jetajockey]

A really nice 2x54w fixture with individual reflectors will get you into the high light range, catalina can custom build a wide fixture specifically for 18" wide tanks. If you want to go even higher, then look at something like their 3x54w fixture.

This is a good chart to take a look at
PAR vs Distance, T5, T12, PC - Updated Charts


I think in most cases the high end 2x54 would be sufficient, but if you aren't convinced it'd be enough, then this 3x54w is definitely more than enough, plus it'll give better coverage over the tank
T5 PLANT GROW HOOD

I'm not partial to any particular brand, this just happens to be one that's on sale at the moment. The key to look for is individual reflectors and customer reviews.

 

[rcherry]

Thanks a lot, all helpful answers.

 

[rcherry]

Wow that Catalina fixture looks like a great deal. How convinced are you that 2 bulbs would put me into high light? Because I would love to be able to use that 3rd bulb as some type of moon light.

Also, I've read a lot about the different temperature bulbs. Some places say it isnt overly important, others say 10000k, some 65000k. I'm thinking some combination of the 10 and 65. I also see this "plant grow" bulb but I really don't know what that's about.

 

[jetajockey]

6500k is the optimal rating to replicate sunlight, but plants can still use 10000k as well. the 10000k gives a crisper white color. A combination of both works out well.

I think that a high quality 2 bulb fixture is plenty for a tank that size, personally, but I'm into the 'less is more' ideology, rather than overkill and then playing a balancing act with the tank later on.


The nice thing about that 3 bulb fixture is that it has two separate switches on it so you can control the amount of bulbs you want to run.