Algae in a Planted Tank
How could anyone have a website about aquarium plants without a least a full page dedicated to algae? It seems to me that in order to understand and control algae you need to first adopt a healthy livable philosophy about algae in a planted tank. I'll share my thoughts and views on the subject and you can decide if anything makes logical sense to you the reader.
Algae comes to every tank, it is unavoidable. The issue is in how well it's controlled and whether it becomes a visible nuisance. I like to relate algae in an aquarium to weeds in an outdoor garden. If after planting your garden you failed to provide food and water for your neat rows of plants what would happen? Weeds would appear and begin to flourish. Even if you water and feed the plants, unless you stay vigilant on maintenance issues you will still encounter nuisance amounts of weeds. The weeds will rob much needed light, food, and water from your garden plants. Algae is like those garden weeds. If you don't provide the plants what they need in regards to light, nutrients, and CO2 they will succumb to an infestation of weeds...err algae. Two issues seem to be very apparent regarding algae in a planted tank. The first, algae is always present. The best you can hope for is to control it so that it looks natural and not distracting from your aquascape and robbing the health of the plants. The second is that algae control is related to giving the plants everything they need regarding lighting, nutrients, and CO2. If you limit any nutrient including CO2 you will be fostering an environment that weeds...err algae will be able to gain the upper hand.
So let's enter into this with the understanding that algae is always present in a healthy thriving planted tank. Let's also be clear that in a healthy thriving planted tank that to spot this algae requires more than a glance. To find and see algae in a healthy thriving planted tank requires carefully looking throughout the plants and tank. Can you or do you want to eliminate every trace of algae? Personally I don't think it's possible, at least not for any length of time. One could bleach all the plants and decorations and have a completely algae free tank for a while I suppose. Too sterile and unnatural for my tastes. The best approach in my opinion is to recognize that algae is part of the tank just like weeds are part of the garden.
Now you have a good idea of my personal philosophy on algae in planted tanks. This page would be less than helpful though if I did not also address how to combat algae when it does get out of control. I'll separate algae into main groups and give multiple options where they exist.
Green Water/Free Floating Algae
Green water or free floating algae is covered on a separate webpage at this link.
http://www.aquariaplants.com/cloudygreenwater.htm
BGA/Blue Green Algae/Cyanobacteria
This is actually an organism that is more closely related to bacteria than algae but we always lump it into algae for ease of discussion. BGA is generally a sign of a tank that is not healthy or that has a high load of dissolved organics. BGA has many species and forms and causes great angst among planted tank beginners and experienced hobbyist alike. Some forms of BGA grow slow and are very difficult to kill, other species grow very quickly and can overwhelm and "smother" all the plants in short order. I have encountered some especially virulent species that wouldn't die without treating the tank with antibiotics.
Treatment Option 1:
Tank blackout. This method is very effective against most outbreaks of BGA. Manually remove as much of the slimy BGA as possible. Then do a large (50-70%) water change and cover the tank with trash bags or thick blankets for 3-4 days. No light whatsoever should enter the tank. Your fish and plants will be fine, some plants like Glossostigma may get a bit "leggy" but you can give it a "haircut" and it will return to proper form in short order. Upon removal of the trash bags/blankets do another 50-70% water change, this helps get rid of all the dead BGA. Dose 10 ppm of nitrate and maintain nitrate at 5-20 ppm throughout the week.
Option 2:
Many times if the BGA is located in just one spot in the tank you can redirect the water current to kill the BGA. Stagnate spots are prime areas for BGA to develop. Generally speaking BGA doesn't like heavy current. I have positioned a power head directed into a patch of BGA and caused it to shrink and even disappear within days. Insuring that water circulation is ample in a planted tank helps thwart BGA outbreaks. Dose 10 ppm of nitrate and maintain nitrate at 5-20 ppm throughout the week.
Option 3:
Sometimes aquarists will inadvertently allow nitrate to drop to zero and remain there for several days to even weeks on end. When plants are nitrogen starved the environment is ripe for a BGA infestation. Increasing current and adding nitrate via potassium nitrate additions can often times eliminate BGA under these circumstances, so dose 10 ppm of nitrate and maintain nitrate at 5-20 ppm throughout the week.
Option 4:
Some species of BGA are extremely virulent. Repeated changes in current, blackouts, nitrate additions...nothing is able to fully beat back the BGA. In these extreme cases it may be necessary to, as a last resort, use an antibiotic such as erythromycin to kill the bacteria. I have had success with Maracyn. Dose at the full rate of 200mg per 10 gallons of water per day and dose for the full five days. Treatment with lower doses or shorter times can lead to not fully killing the bacteria and "could" lead to a more resistant strain. Like the use of any medication this should only be considered after repeated other methods fail. Do a 50-70% water change after the full treatment and dose 10 ppm of nitrate and maintain nitrate at 5-20 ppm throughout the week.
Brown/Diatom Algae
Except at startup this is not an algae that should be visible in a healthy planted tank. Otos or Otocinclus affinis are excellent little fish that will remove and keep this algae in check in a planted tank. I like to use one Oto per sq. ft. of tank bottom.
Green Dust Algae
This is that dusty looking algae that coats the front and side glass. It's generally a good sign if that’s the only algae that is noticeable in your tank. A quick scraping of the glass prior to your water change is all that's needed to control this non nuisance algae.
Green Spot Algae
These are hard circular algae spots that take hard scrubbing too remove from the tank glass. It's been my experience that moderate to high light phosphate limited tanks have more problems with green spot algae on plants. A plant expert from online forms, 2la (Tula Top) suggests using Rubbernose Plecos. My limited use has shown they are excellent at reducing green spot algae on plants, but that they are very tenacious raspers and may cause some tissue damage on leaves, like Anubias that remain in the tank for long periods being rasped on constantly. If you have issues with Green Spot the Rubbernose Pleco is certainly worth a try in your tank. Green Spot Algae is often eliminated with increasing phosphate levels in your water. Try to maintain at least 0.3 to 0.5 of phosphates throughout the week and more preferable is in the range of 1.0 - 2.0 ppm of phosphates.
***************************************************************************************************************
Most of the filamentous forms of algae are born from a root cause associated with an ammonia spike, whether detectable or not. The ammonia might have been from too major of a pruning, excessive substrate disturbance, increasing the bio-load too much, allowing plants to stall from either being CO2 limited or being limited from another nutrient. Often times the root cause (ammonia) is gone and not detectable, but if the cause of the initial ammonia spike is not rectified then algae will just continually recycle. Here is a short list of some of the major forms of algae and following that is the systematic approach I use to address the root cause, and then the course of action to eliminate and control the algae.
Thread/Hair Algae
Most Thread/Hair algaes grow extremely fast. You can manually remove handfuls every couple of days. After eliminating this type of algae is it a good idea to add an algae eating crew. Personally I have great success with SAE's, Rosy Barbs, American-Flag Fish, Amano Shrimp, and Bristlenose Plecos.
BBA/Black Brush Algae/Black Beard Algae
Personally this is the most objectionable looking algae to me. Controlling BBA is fairly straightforward thankfully. Make sure that under moderate to high light conditions that CO2 is in a range of 15-30ppm. Fluctuating CO2 levels as found with DIY yeast injection seem to be more likely to cause an outbreak of BBA. The best control is the use of an algae eating team of experts. Siamese Algae Eaters (SAE) are very good at keeping this algae in check. I have also noticed some individual Rosy Barbs will snack upon BBA too.
The systematic approach to eliminating algae problems.
It is critical to find the root cause of your algae problem if you want longterm success. Taking a systematic approach will address all the potential areas that could have led to an ammonia or organic overload issue that fueled the algae problem. Rather that taking a guess at the cause and effect, it is far better to start from the beginning and correct errors as you find them. I like to call this the shotgun method. Rather than taking aim at what you "think" might be the problem and shoot a single shot, I'm encouraging you to send a shotgun blast at everything that is not right. That is not to discount the value of making one change at a time and watching the results...but reserve that method for when you don't have a tank full of algae. Here is the method I use to fix those times when algae becomes a nuisance.
How is your lighting? Too much lighting. Wrong type of lighting. Too little lighting. Too long or too short of a photoperiod. Poor choice of substrate for the type of planting and lighting.
How much overall plant mass and species and overall fish load? Too little plant mass or too many slow growing plants for the lighting will need to be fixed. A major issue is too many fish, too large of fish for the maturity of the planted tank.You might need to increase the amount of plants, or changing to lower light plants or faster growing plants to match the lighting and substrate. Trying to run a soil substrate with high lighting is a recipe for algae issues.
What is the GH, KH, and pH of your tank? If GH is below 3 there may be an issue with a calcium or magnesium deficiency.
Determine the CO2 concentration of the tank, and the tank water when degassed. Using the KH and pH determine CO2 levels using a CO2 chart or online calculator. Make sure to check a degassed sample against tank water. Degassing means that you remove a couple of cups of tank water and place the water in an open bowl over night so that all the injected CO2 can degas. The next morning take a KH and pH reading of the degassed water in the bowl. Compare the degassed sample with the tank water. You should see a 0.6 to 1.0 difference in pH between the two if you are to have CO2 levels within the range needed for plants under strong lighting and to insure they aren't CO2 limited. This is the most important point to focus on in tanks that have over 2wpg of lighting. A large portion of algae problems are CO2 related so pay close attention to this very important issue.
Be honest about the need to make adjustments lighting, fish load, or plant mass...without addressing these core issues you'll not achieve longterm algae control.
Once all the issues have been addressed and changes made the next steps are pretty much the same except for BGA and Green Water. The steps should always follow this order and never proceed to the next step until certain of success with the previous step. For example, don't do the water change prior to manual algae removal and don't dose any nutrients until CO2 levels are confirmed. (if CO2 is being injected)
1. Manually remove as much algae as possible, even if that means removing some leaves if the algae is firmly attached such as with BBA.
2. Do a 50-70% water change.
3. Confirm that CO2 levels are 20-30 ppm. (if being injected)
4. Dose enough KNO3 or equivalent to add 10 ppm of nitrate to the entire tank volume.
5. Dose enough K2SO4 or equivalent to add 10 ppm of potassium to the entire tank volume.
6. Dose enough KH2PO4 or equivalent to add 1 ppm of phosphate to the entire tank volume.
7. Dose a trace nutrient (micro) provider such as Seachem Flourish, Tropica Plant Nutrition, CMS+B per label directions for the entire tank volume.
Repeat the 7 steps at least twice per week, though every other day is even better...do this for two weeks, then return to weekly water changes and a dosing schedule based on lighting and CO2 levels.
Hopefully you gained something from reading my experiences and views. Please understand that I make no claim of being an expert with all the answers. Others may have completely different experiences and you should always seek out alternative points of view.
For answers to specific questions check out
Tropical Resources, the Web-Forum provider for Tropical Fish Hobbyist Magazine and say hello to me while you are there!
Tropical Resources, the Web-Forum provider for Tropical Fish Hobbyist Magazine and say hello to me while you are there!
