Simple Lighting Question...I think

[Myka]

I'm wanting to upgrade my current ghetto fabulous industrial spiral compact flourescent lighting to a nicer looking T5 fixture. My tank is 24" long, and 15" from water surface to substrate surface. I have a heavily planted tank with Echinos, Crypts, Rotalas mainly. No CO2 currently, although I am considering adding pressurized I'm just not sure I want to put that money into this small tank. I do want to utilize two bulbs so I can play with Kelvin a bit for a nicer look.

Now, I think I have it figured out, but I just want to check. I think I should use 2x18w T5 with no CO2, and 2x24w T5HO if I decide to add CO2. Is that correct? Is it possible that I could use one of those fixtures with either CO2 or no CO2? I don't want to have to re-upgrade if I decide to add CO2, and I don't want algae issues due to too much light if I decide not to use CO2.

Any thoughts?

 

[Philosophos]

two bulbs makes for more even spread and more fun with color; you're definitely on the right track there.

You can run CO2 with any level of lighting; it's good for any planted tank. The 2x18w might be a bit on the upper edge of non-compressed, meaning you'd probably want DIY CO2 along with excel at this level. I tend to keep my non-co2 (compressed or otherwise) tanks at 1.5wpg and below; even then a little BBA pops up on occasion.

If you go with compressed, it's a good long-term investment. Buy it and play around with it on your small tank, get a bigger tank later. Small tanks make for smaller messes when you're trying new things, which is easier on the wallet.

-Philosophos

 

[Myka]

Thanks Philosphos!

I have one of those Hagen CO2 canisters so I can do DIY CO2, and I have a really good recipe that gives me 1 bps for 2-3 days, and I can keep it quite steady. However, I always end up getting BGA when I try to use it. I was thinking of trying a second canister, and change each one every second day so that there is a fresh batch everyday. That should give steadier results? I was leaving the CO2 running at night though, maybe that was the cause of issue? My recipe makes 1 1/2 bps in about 2 hours, and peaks at 2 bps in 6 hours which it will run for about 8 hours, and then back to 1 1/2 bps for about 20 hours before it tapers off.

Isn't wpg a bit neanderthal? Do planted tank people still use that? Sorry, I've only been into planted tanks for a year. Mine is a 20 gallon, but it is an irregular shape being 17 1/2" tall, so I would need slightly stronger lighting in comparison to someone running a 20H or 20L, right? Having been into reef tanks mostly for the last 15 years or so tends to make me want to light the bejesus out of the tank! LOL! I currently have 49 watts on it using compact spiral flourescents in lamp shade style reflectors at about a 45 degree angle to the water. The light spread is poor, so there is rather a spot light effect. If it was more evenly spread I think that ends up being about the same intensity as using 2x18w T5s, no? And my Glosso is stretching to almost 3" tall, which means not enough light, doesn't it? I could go on and on about reef lighting, but I'm rather lost when it comes to planted freshwater tanks. Hahaha.

I won't be getting a larger tank, no worries there. I have a 90 gallon reef too. Although I have had many tanks bigger than the two I have now in the last 20 years, I have no intention of getter any larger tanks again. I like the ones I have now. I do plan to set up a couple banks of marine breeders again though. Winter project.

 

[Philosophos]

Rotating CO2 canisters will work just fine for the lower light level. The only exception I could think would be if you're using individual parabolic reflectors, with two separate fixtures spread evenly over the tank. You might be a little high on light if you do it that way.

WPG is a mangled relative term. PAR is better, but most of us don't have a PAR meter sitting around; if we all had them, we'd just say "make sure what ever it is, that you get around 50mmol PAR".

I use WPG as a base line that I modify a bit for each fixture; if some one is using CF, they output pretty similar levels of light to each other. If it's t8/t5/t5ho I tend to look at it as the same as CF until height from water , spacing, and high quality reflectors come in to the issue. In the case of your spiral CF, I anticipate anywhere between a 30-50% loss in efficiency. Most of the time it becomes a good base line for the initial purchase, with the chosen light being a hair over powered. From there the fine adjustments get made according to the setup an individual has.

I'm not sure as to the reputation of the product, but aren't calcium reactors common to reef systems? If you went with CO2 you could split the lines, and have the reactors for your reef tanks while injecting CO2 in to your planted tank.

-Philosophos

 

[VaughnH]

I think two 18 watt T5NO bulbs, with individual, highly polished aluminum reflectors will give you around 100-120 micromols of PAR at the substrate. That is high light intensity, requiring CO2 to have much chance of avoiding lots of algae problems. One T5NO bulb might work ok without CO2, but even that would be questionable. Since your tank is only about 10 inches front to back, one bulb would give a uniform enough light intensity, but wouldn't let you mix different color temperature bulbs.

Now, if you use a two bulb fixture, and hang it above the tank, perhaps about 8 inches above the water line, you should be able to do ok without CO2. That also reduces the range of light intensity from substrate to water surface, evens out the intensity over the substrate, and allows you to lower it for more intensity if you decide to use CO2 later.

Look for Tom's bent conduit method for hanging a light fixture if you want to go that way.

 

[Myka]

Philosophos, I don't have a calcium reactor on my tank. Calcium reactors are becoming a thing of the past as liquid dosers are taking over. Currently I manually dose my reef daily with powdered calcium, buffer, and magnesium. I do plan to upgrade to a doser, but I have a few other upgrades planned before that pricey one. I should buy a PAR meter. The problem is that most people have no clue what I would be talking about if I said I have X mmol PAR. Haha!

VaughnH, I was planning to use a Hagen GLO fixture on the planted tank, they just come with a single half-cylinder shaped smooth reflective reflector so they aren't overly good. I was hoping this might help keep the par low enough. Hagen has come out with a higher quality reflector you can upgrade to, but it is still a single reflector for both bulbs, which I could incorporate if I found the PAR was too low. I can also choose to use high or low quality bulbs to increase or decrease PAR. I was planning on using the legs that come with the fixture which places the bulbs about 4" from the water surface, but I do like your idea to raise or lower the fixture. Thanks for suggesting the conduit, I will go check that out now, it sounds interesting! Oh, and my tank is 13" front to back...it is an odd shape.

Thanks for the replies guys! Much appreciated.

 

[Philosophos]

there's a group buy on for par meters right now at a heavy discount:
http://www.barrreport.com/general-plant-topics/6054-group-buy-par-meter-228-us-shipped-via-paypal-payments.html

Many of the more serious planted tank keepers are using PAR. Hopefully basic PAR formulas and readings will replace WPG rules as things progress.

-Philosophos

 

[Myka]

Wow, that's a great price, but unfortunately instead of spending that money on a PAR meter, I have more important upgrades to think about right now.