[gottobe]

I have had my 125 gallon tank planted for about 2 months and things were initially going pretty well. The plants were growing pretty good originally but seem to taper off after about a month. I placed some more plant tabs near the swords and I made some changes in the length of time that I was running my lights and now have better plant growth but also a fair amount of algae. I dose with Flourish twice a week in the recommended amounts, and with my double drop checker and pretty confident in my CO2 levels. I would like to figure out what to do because, I can clean off the algae on the glass but its different story on the plants. Can anyone make a recommendation that would help limit algae growth on my plants?

Here is a more detailed description. I have (2) 36" Current Sundial Lights (w/ 4 10,000K plus 4 fresh water bulbs). Each bulb is 39 watts so that's 312 watts or 2.5 watts per gallon. Originally, I ran the fresh water bulbs about 11 hours and kicked in the 10,000k bulbs for an 8 hour run. That resulted in a somewhat stunted plant growth. So I added 2 hours to the fresh water bulbs and now have a bit of an algae problem brewing. I also have an 18 watt Coralife UV Sterilizer inserted on one of the Eheim outflows, which I run for about 8 hours every few days.

More information on my set-up is found at http://www.aquaticplantcentral.com/forumapc/aquascaping/52845-125g-office.html

Below are pictures of the algae growth I am experiencing.

 

[MatPat]

In my opinion you are underdosing your tank with Flourish. The amounts that Seachem recommends are for a normal planted tank, not one with CO2 and high light. A daily dosage of the recommended amount would probably be a much better starting point than twice weekly dosage.

 

[Cavan Allen]

I concur. You need to be adding much, much more Flourish. I usually recommend equal amounts of Flourish and Flourish Iron, daily if possible.

 

[Complexity]

With a tank as large as yours, I would switch from Flourish to dry ferts. They're much cheaper, very easy to use, and have a great success record.

Your photo period is very long. Did you say that you're now running the "freshwater bulbs" for 13 hours? That may be too long. I was running 1/2 of my bulbs for 12 hours with just a few hours of all my bulbs, and even with EI ferts, the plants didn't do as well. I now run all 4 bulbs for 7 hours with incredible growth!

The main goal is to strike a balance between the lights, ferts and CO2. I also think plant mass is an important aspect to keep in mind while trying to find the right balance.

You want to inject as much CO2 as you can, just below the amount that stresses the fish. If you have a drop checker, you should be able to get the color to a yellow or yellow-green.

I like to use EI fert dosing. The idea behind this is to supply more ferts than the plants need so they will always have ample ferts to grow their best. Then reset this with a weekly 50% water change.

The last element, but sometimes the trickiest, is the lighting. The lighting drives everything. You want to give enough lighting for the plants to grow at their best, but not so much that algae can take hold. This can be a challenge to set up in the beginning. But, basically, bright lights grow plants very nicely, but if they are turned on for too many hours, algae will take over. More light for fewer hours seems to work best for me. You'll have to experiment here.

I also believe plant mass is a very important element in the fight against algae. You need to have lots of plants to fend off algae. If you're low on plant mass, add "weeds" such as hornwort until you have enough plants or your plants have grown in.

Some people think if you have fewer plants, you should just dose less ferts, but I disagree. The amount of ferts you dose determines the saturation of the ferts in the water column. If you reduce the ferts, you're diluting the ferts for the plants. They don't get all the ferts in the water column, just what they can come in contact with. So if the water has a diluted amount of ferts, the plants can only get a diluted amount of ferts. If you dose a maximum amount of ferts, now all the plants can obtain all the ferts they need. However, if you don't have enough plant mass to use up the ferts, then algae will do it for you. So it's important to keep the plant mass high enough to keep the algae at bay.

My suggestion would be to max out your CO2 and switch to dry ferts using the EI dosing method. Make sure you have a good plant mass. And then experiment with the photo period until you can give the plants as much light as they need for good growth, but not too much that algae can take over. The overall concept is to max out everything and then work with the lighting photo period to get that last element balanced.