How long before I start to see an algae explosion?

[punk-in-drublic]

Ok so I bought a new lighting system for my 75G. Its a 2x54 watt T5 with what seems like a solid reflector. The lighting is about 20 inches from the substrate and I am not running CO2 in this tank or dosing any ferts. Im on a 10 hour photo period currently. Also I am doing weekly 25% water changes. Probably underfiltered I am running 1 AC 110 for filtration.

The tank currently is what I would describe as lightly planted. I expected the possibility of algae when I bought the fixture with the intent of possibly removing one of the bulbs should it start to get nasty in there. I really wanted to have a fixture that would give me enough light to plant most species of plants.

So far the water is extremely clear and I haven't had any real visible algae. My question is how long do you expect before I will start to see algae blooms based on your own experiences with lighting. Is it possible that I may not see tons of algae with enough plants and consistent water changes or am I in for a mess in 2-4 weeks?

If I do begin seeing algae blooms what should my first course of action be? I was thinking about taking action in this order:
I am trying to avoid adding ferts or co2 at this point however if you feel it would be a better course of action then the one I have below please let me know.

1.) Reduce photoperiod
2.) Add versatop (not sure if this will be significant in reducing the overall level of light hitting the tank)
3.) remove 1 bulb.

Thanks for reading.

 

[jcardona1]

yeah it should be fairly soon i say. that is too much light, no way around it. you need to understand that the more light you have, the more your plants will demand co2 and ferts. if you dont meet these needs, youll get algae because the plants arent getting the nurtients they need to outcomplete algae. i would:

- use normal output bulbs, or
- add co2/ferts, or
- run one bulb only and raise the fixture more

 

[jcardona1]

and for what it's worth, i had the same over a 55g, 2x 54w bulbs. even with lots of co2 and ferts i still had a few algae problems...

 

[punk-in-drublic]

So it looks like I have 3 viable options. With a fourth option that is unlikely to be successful

1.) buy a new fixture with lower light output.

I really don't want to go this route Im really liking this fixture and feel like I could potentially want to go Full dosing and CO2 later on.

2.) start dosing ferts and CO2

I wasn't quite ready to throw down the upfront cost on a CO2 system right now. I could do it but I would prefer to wait a few months at least if I can.

3.) Raise the lighting further from the substrate and potentially run only one bulb.

This is not a great option for me I cant really suspend from the ceiling in my current apartment and I would have to build a lightstand of some kind which I'm not thrilled about.

4.) wait and see what happens.

Im considering a mixture of option 4 and option 2 followed by option 3 if things get nasty. Is it worthwhile to begin dosing ferts without co2 or is that relatively pointless?

Also would a significant amount of floating plants do anything to help the situation? Just as another thought.

I feel like I made a noob planted tank error that hasn't bitten me in the ass yet and I am just waiting for the sting so thanks for the input and I will keep everyone informed of the progress.

 

[bob965]

You might want to consider using flourish excel if you're not going to use co2.

 

[punk-in-drublic]

yeah it should be fairly soon i say. that is too much light, no way around it. you need to understand that the more light you have, the more your plants will demand co2 and ferts. if you dont meet these needs, youll get algae because the plants arent getting the nurtients they need to outcomplete algae. i would:

- use normal output bulbs, or
- add co2/ferts, or
- run one bulb only and raise the fixture more

So J, based on my calculations and with the help of your stickied thread which is very helpful by the way. I've calculated that my tank is currently at about 120 micromols of Par based on two t5ho bulbs about 20 inches away from the substrate. Im considering suspending my light fixture higher to avoid the giant algae bloom that could be impending. What level of intensity do you feel is a good level to shoot for if I wanted to avoid pressurized co2. Should I be aiming for the low light category or would I be ok in the mid light category. My Thinking is that if I can raise my light somewhere between 5-10 more inches from the substrate I will be in the high middle to middle light intensity range and maybe in a better situation regarding my intensity level. If that is still not low enough I'm going to need to rethink the situation a bit. Thanks!

 

[punk-in-drublic]

You might want to consider using flourish excel if you're not going to use co2.

I dont know much about the difference between using a liquid carbon source versus pressurized CO2. However Im assuming the pressurized co2 is probably going to be cheaper over the very long term. What are some of the other differences between the two. Pros and cons for each side? Thanks again.

 

[jcardona1]

So J, based on my calculations and with the help of your stickied thread which is very helpful by the way. I've calculated that my tank is currently at about 120 micromols of Par based on two t5ho bulbs about 20 inches away from the substrate. Im considering suspending my light fixture higher to avoid the giant algae bloom that could be impending. What level of intensity do you feel is a good level to shoot for if I wanted to avoid pressurized co2. Should I be aiming for the low light category or would I be ok in the mid light category. My Thinking is that if I can raise my light somewhere between 5-10 more inches from the substrate I will be in the high middle to middle light intensity range and maybe in a better situation regarding my intensity level. If that is still not low enough I'm going to need to rethink the situation a bit. Thanks!

that could work. ideally, youll want to be in the low light category. medium light is a toss up, it may work it may not. i'd say aim for the bottom of the medium light category and go from there

 

[jcardona1]

I dont know much about the difference between using a liquid carbon source versus pressurized CO2. However Im assuming the pressurized co2 is probably going to be cheaper over the very long term. What are some of the other differences between the two. Pros and cons for each side? Thanks again.

excel can effectively replace co2 injection in smaller tanks, less than 30g. once you get bigger than that it's hard to get good carbon levels on excel to support decent plant growth. at this point youll want to consider DIY co2. DIY co2 also has its limits, and on a tank your size the most efficient thing to do is pressurized co2. it's a little expensive to start up, but very cheap in the long run.

 

[punk-in-drublic]

excel can effectively replace co2 injection in smaller tanks, less than 30g. once you get bigger than that it's hard to get good carbon levels on excel to support decent plant growth. at this point youll want to consider DIY co2. DIY co2 also has its limits, and on a tank your size the most efficient thing to do is pressurized co2. it's a little expensive to start up, but very cheap in the long run.

Thanks J thats helpful. I have thought about trying the DIY solution on my 75, I currently have a setup running on my 10g which I find pretty easy to manage but I don't think I want to run 6 bottles underneath the tank if I can help it also everything I have seen seems to say that it won't be very effective for a tank this large similar to your comments above.

Do you have any recommendations for a guide on beginning dosing ferts?