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Using Seachem Excel as spray-on algecide

6918 Views 13 Replies 9 Participants Last post by  Jeff5614

I know some folk have used Excel as spray-on algecide to target troublesome algae. Excel can be sprayed on plants when water is low during water change, or by removing the plant an then applying spray.

Any procedural tips on how to do this?
Limitations / warnings?
How much water to mix with how much Excel?
How long to leave the spray on before submerging the plant? Some species do vs. don't try?

My own interest is in treating hair/thread algae on clumps of needle-leaf java fern, but I'm curious about any experiences.

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I dont know if I would spray it on the leaves when they are out of the water. I have had good luck with turning off my filter or whatever water movement implements that are in the tank and getting a syringe and spraying it in the area of infestation. Then leaving the filter off for an hour or so then resuming filtration. On BBA the next day or two you will see it turn purple/pink/white/gray then its dead.
I use H2O2 spray for the same purposes. It works just as well IMO and it's a whole lot cheaper.
I mixed some with 3 parts water to 1 part Excel and sprayed it on some moss that was developing a bit of BBA while the moss was above the water during a water change. The good news is that it killed the BBA. The bad news was that the moss took a beating which I was concerned it might. I also sprayed it on a patch of GSA that was on the glass and three days later the GSA had turned white. I'm not sure how it will affect the ferns though.
Don´t spray it to the plant directly outside the water because it will melt the leaves of the plant. Happened to my poor anubias. The H2O2 can be sprayed to the plant outside and it is less harmful.

What I do is fill a syringe with the Excel, stop all filters and spray it in the tank directly above the plant.

After that I follow with a blackout for a day. By the next day the BBA turns pink.

I have found that doing a once a week blackout (leaving lights off, not covering the whole tank) has helped a lot in controlling BBA in my tank. Plants have not been affected by this procedure so far
I agree: I turn off the filter, fill a syringe with 100% Excel and squirt it directly on the problem algae. I turn the filter back on in 15 minutes.

However, make sure that how much Excel you're using doesn't exceed a double or triple dose; you don't want to add TOO much to your tank. If you're adding the equivalent of more than a daily dose, work up to it over several days; don't just add a triple dose on one day because that could shock your plants. I use 6 ml a day when treating BBA in my 29 gal (roughly 2x dose). If you can't spray all the algae in one day, do the patches you missed on the next day.

Be especially careful if you have Vallisneria sp. in your tank; they don't take well to sudden increases in Excel.
i also spray h2o2. you can buy a spray bottle trigger and buy a one quart bottle of h202 and it will screw right on the bottle.
Thanks, this is helpful.

When using H2O2, what was your procedure?

100%, sprayed on plants out of water, how long did you leave it before re-filling tank or resubmersing plant?

The H2O2 spray is pretty straight forward, just put standard hydrogen peroxide (3%, the stuff from the grocery store) in a spray bottle and spray it on affected areas. I've used it on my java moss, java fern, anubia nana petite, tiger lotus and amazon sword. There are also a few other ways to do this. I use a little 10mL syringe (without a needle) and spray the H2O2 directly on the leaves in the tank when doing a water change. The H2O2 is safe for the fish as long as you keep it around ~2mL/gal/day. I've actually heard dosing this daily can lead to healthier fish. Finaly, you can remove your affected plants and submerge them in a H2O2 bath for a few minutes if they are really bad. I did this after a BGA outbreak and it worked wonders. Hope I answered your questions!
A word of caution using H2O2. While 2x the recommended dose of excel can be used repeatedly in the same area day after day without hurting most plants H2O2 cannot be. Repeated dosing by syringe or applied directly to leaves exposed at water changes will damage the leaf after about three or four doses if done daily. Even if using only 3% topical hydrogen peroxide.

HP is a weak acid and has strong oxidizing properties. It is a powerful bleaching agent. The oxidizing capacity of hydrogen peroxide is so strong that it is considered a highly reactive oxygen. (Wikipedia)

I used H2O2 daily after feeding my fish. Directly spraying it on submerged anubias leaves with a 10ml syringe treating GSA. While it killed the algae it burned the surface of the leaf damaging some bad enough I just cut them off. The same thing occured treating a large java fern for BBA. The leaves that were sprayed daily for five days developed holes and a lighter color in the area that was treated repeatedly.

Doing the same thing with excel for over two weeks straight hurt only the algae. This tank is just now starting to show GSA returning after about 4 weeks. A side benefit also was that even though one of the tanks I did this in is injected with CO2 the plants all reacted to the excel dosing with a noticable growth increase.
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I wasn't online yesterday to see the confusion on the application of excel from the OP.

There are several really good threads on TPT dealing with using Excel to knock down algae. What I've read has members using as high as 6.65ml/10g. What I have personally done is using a syringe dosed .5ml/1g (5ml/10g) daily for eight days without ill effect to anything but the target algae. The ratio I used is actual tank volume not listed tank size. On a 75g tank after adding substrate and driftwood etc. the tank actually holds 60g of water. This is what Seachem's directions state as the initial dosing ratio after a major water change so the only 'overdosing' was the fact it was done daily.

I do not spray the excel on emerged plants (out of the water). Shutting down my circulation (filter and or power heads) I allow the tank to 'rest' for several minutes then with a filled 10ml syringe I slowly reach into the tank and hold the syringe within about 1/2" of the algae and spray the excel onto it. I then wait 15/30 minutes depending on how much tank work I'm doing on my other systems then restart the pumps. The only plants I've had problems with are my chain swords doing this. Looking back at my records over the last two years the longest I've done this was eight days then a 25% WC. (I've used lower amounts for longer periods in my low tech tanks. 5ml/20g)

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when i treat with excel i pretty much follow the same idea with 5ml per 10g. the only difference is i do it during a 50% water change. when the water is half out of the tank i dose and let it sit for about 10 minutes while i'm taking care of the rest of the tanks. at that point its a pretty high concentration of excel and does excellent at treating algae. then i fill the tank back up and its at the same level as wkndracer would dose.
I apply it using a baby aspirin syringe with a piece of vinyl tubing attached to the end. I've done this to feed fry as well, I inject food around the rocks they live in, that way they don't have to risk being eaten of they leave their hiding places

sent from my phone, because I can't get the internet out in the boonies.
I was reading a suggestion on another forum to use a small paint brush to apply it directly to areas to avoid as much "collateral damage" as possible.
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