Jarstar, How long has this pond been set up? Have you tested your water for ammonia, nitrites, nitrates and ph? If so what reading did you get? What kind of water changes are you doing? How are you cleaning the filters? I am fairly new at this myself, but have had plenty of saltwater reef systems, so all I can suggest right now is to do 20% water changes weekly and rinse the filters with water from the pond. Try and answer some of the questions and hopefully somebody with more experience than I have will come along and help. Hope this helps a little. Teri

The problem won´t go away if you do not correct the cause, you may use algicide over and over again and the problem will come back, it´s like trying to cover the sun with a finger. The cause of algae blooms is: too much light and too much free nitrogen in your tank. Light can be corrected by shading the place where the tank is located or by reducing the hours of light ( by turning off the lamp ), free nitrogen on the other hand is a little bit more tricky, the most common causes if increased nitrogen levels are: to many animals ( a large biomass ) or too much food, food that decomposes and turns into ammonia, nitrites and nitrates. Reducing the biomass, increasing water changes and reducing the ammount of food restores the balance to the system. You need to use both approaches, reducing the light levels and reducing the ammount of free nitrogen, that way the algae will not have two of the elements it needs in order to grow.

I found this bit of information also. "Brown algae" (diatoms) This is often the first algae to appear in a newly set-up tank, where conditions have yet to stabilise. It will often appear around the 2-12 week period, and may disappear as quickly as it arrived when the conditions stabilise after a couple of months. It is essential to minimise nutrient levels to ensure the algae disappears - avoid overfeeding and carry out the appropriate water changes, gravel and filter cleaning, etc. Limiting the light will not deter this algae, as it can grow at low lighting levels and will normally out-compete green algae under these conditions. If brown algae appears in an established tank, check nitrate and phosphate levels. Increased water changes or more thorough substrate cleaning may be necessary. Using a phosphate-adsorbing resin will also remove silicates, which are important to the growth of this algae. However, as noted above, it is essentially impossible to totally eliminate algae with this strategy alone. Due to its ability to grow at low light levels, this algae may also appear in dimly lit tanks, where old fluorescent bulbs have lost much of their output. If a problem does occur, otocinclus catfish are known to clear this algae quickly, although you may need several for larger tanks, and they can be difficult to acclimatise initially. There are some very plausible theories as to why this algae often appears in newly set up tanks and then later disappears. If the silicate (Si) to phosphate (P) ratio is high, then diatoms are likely to have a growth advantage over true algae types and Cyanobacteria. Some of the silicate may come from the tapwater, but it will also be leached from the glass of new aquaria, and potentially from silica sand/gravel substrates to some extent. Later, when this leaching has slowed, and phosphate is accumulating in the maturing tank, the Si:P ratio will change in favour of phosphate, which is likely to favour the growth of green algae instead. Green algae A certain amount of green algae is likely to occur in any tank with sufficient lighting. It is eaten by most algae eating fish and is generally fairly easy to remove from the tank glass. Hard 'green dot' algae This appears as small round dots on the aquarium glass. It appears to be a normal part of planted tanks with higher light levels. Algae-eating fish will not remove this algae and manual removal requires hard scraping. Magnetic algae scrapers are usually inadequate, unless the edge of one half is used inside the tank - or use a razor blade.

I do weekly water exchanges with water from my aquarium shop, I do about 8-9 gallons a week. I am leaning more towards diatoms as I couldnt find a pic on the net of what I have and the brown algae pics I saw dont look like what I have.. My setup has been weird from the start, I once had a huge jellyfish outbreak, which went away eventually but the other day I noticed a few more returning.. I now also have about 10 aiptasia's but will be killing those when Joe arrives in the mail.. I do feed alot but water test all came back fine.. my salinity was high for a while but is now back to normal level.. I dont really have any corraline algea on the back walls and never have which the aquarium pros are a bit puzzled by.. I also had a huge coral die off as well a few months back which was never explainable... not sure what to do about the light as I cant really change it; well I could change the bulb its currently a 12k.. I also have the buffer stuff that comes in a bag down in the plumbing which is supposed to help filter the water.. I do have purple algae on the back walls but it looks more to be the long hairy type and not yet corraline.. and each water exchange I do add a couple drops of the Luigis solution.. not sure what else to do besides keep on scrubbing each water exchange.. attached is my site, all the pics are old, but a few close up pics of the fish you can see some small dots, this is when it just starts and then gets progressivly worse.. check the second yellow tang pic, I think that has the best shot of it.. Here is a link that might be useful: my tank