Does anyone know the cheapest place online to buy Physan?

[DavidCampen]

The active ingredients in Physan - benzylalkyl ammonium chlorides (also sometimes referred to as quaternary ammonium chlorides or simply "quats")
are used as a disinfectant in many other products. Swimming Pool and Spa supplies are a good place to look, it is used to control algae, you will need to go to Walmart or Canadian Tire and read labels.

Here are a couple of products:
Algaecide (5%), 4L | Canadian Tire

Liquid Algaecide 15%, 3.78L | Canadian Tire

[silken]

The other thing you could look into is a similar product called KleenGrow which is another quaternary ammonium chloride chemical similar to Physan. We had a local garden centre order some gallon jugs in for a few of the members of our society. It is used to clean greenhouses but also in lower doses to treat orchids, bulbs etc. etc. as a fungicide. I can't really help with where to order it from or anything but I believe there is a Canadian source. KleenGrow

Actually these guys are in Burnaby B.C.!

[Wild Orchid]

Originally Posted by DavidCampen

The active ingredients in Physan - benzylalkyl ammonium chlorides (also sometimes referred to as quaternary ammonium chlorides or simply "quats")
are used as a disinfectant in many other products. Swimming Pool and Spa supplies are a good place to look, it is used to control algae, you will need to go to Walmart or Canadian Tire and read labels.

Here are a couple of products:
Algaecide (5%), 4L | Canadian Tire

Liquid Algaecide 15%, 3.78L | Canadian Tire

Thanks for this info, David and Silken!
In fact, I've already bought a bottle for Algae-Kill 40% from the Wal-Mart.
Can you advise on dosage though? I'm concerned that this is a very strong, concentrated stuff and I'm not sure that even a drop or two per gallon could cause harm rather than help?

Thanks again!
Lilia

[DavidCampen]

Originally Posted by rlilia

... I've already bought a bottle for Algae-Kill 40% from the Wal-Mart.
Can you advise on dosage though? I'm concerned that this is a very strong, concentrated stuff and I'm not sure that even a drop or two per gallon could cause harm rather than help?

Thanks again!
Lilia

The appropriate concentration depends on your intended use. You can check the Physan website, they give recommended dilutions for a number of different applications - if you don't mind that the recommendations are given in teaspoons per gallon. The Algae-Killl 40% is twice as concentrated as Physan so you would use 1/2 as much.

200 ppm active ingredient is the standard concentration for use as a sanitizer in food handling. I use 2000 ppm active ingedient in the greenhouse for sanitizing tools, containers, floors etc but I would not spray this directly on plants. To spray directly on plants I would probably use about 100 ppm.

Algae-Kill at 40% AI is 400,000 ppm AI so to prepare a 100 ppm AI solution you would add 1 ml of Algae-Kill 40%
to 4 liters of water.

I see that for applying to orchids to treat rot, Physan recomends using 1 tsp of Physan 20 per gallon. This is about equivalent to 5 ml Physan-20 per 4 liters or 250 ppm AI. To prepare a similar solution using Algae-Kill 40%you would use 2.5 ml of Algae-Kill 40% diluted to 4 liters.

Physan 20 Mixing Guide

I actually don't use Physan-20 but another brand from Southern Ag called SA-20.

[Wild Orchid]

Originally Posted by DavidCampen

The appropriate concentration depends on your intended use. You can check the Physan website, they give recommended dilutions for a number of different applications - if you don't mind that the recommendations are given in teaspoons per gallon. The Algae-Killl 40% is twice as concentrated as Physan so you would use 1/2 as much.

200 ppm active ingredient is the standard concentration for use as a sanitizer in food handling. I use 2000 ppm active ingedient in the greenhouse for sanitizing tools, containers, floors etc but I would not spray this directly on plants. To spray directly on plants I would probably use about 100 ppm.

Algae-Kill at 40% AI is 400,000 ppm AI so to prepare a 100 ppm AI solution you would add 1 ml of Algae-Kill 40%
to 4 liters of water.

I see that for applying to orchids to treat rot, Physan recomends using 1 tsp of Physan 20 per gallon. This is about equivalent to 5 ml Physan-20 per 4 liters or 250 ppm AI. To prepare a similar solution using Algae-Kill 40%you would use 2.5 ml of Algae-Kill 40% diluted to 4 liters.

Physan 20 Mixing Guide

I actually don't use Physan-20 but another brand from Southern Ag called SA-20.

THANKS SO MUCH, David.
This is very helpful!

Lilia

[s.kallima]

from everything I read about it, Physan is a good bactericide, but not so much a good fungicide. On of the questions to ask is what do you want to treat with Physan? It works great on algae indeed, and to prevent bacterial infections, but no luck if you have Phytophora or fungi of that kind!
I don't think there is any systemic fungicide available in Canada for hobbyist.

[Wild Orchid]

Originally Posted by s.kallima

from everything I read about it, Physan is a good bactericide, but not so much a good fungicide. On of the questions to ask is what do you want to treat with Physan? It works great on algae indeed, and to prevent bacterial infections, but no luck if you have Phytophora or fungi of that kind!
I don't think there is any systemic fungicide available in Canada for hobbyist.

From the same website that David provided, here are the Phsan applications for orchids.

Physan 20 Orchids

No, you're right, systematic is not available either.

Lilia