Safe pothos?

[Epiphanaea]

I have seen lots of recommendations that having pothos growing out of your aquarium will help keep nitrites and nitrates down.  Where do you get pesticide-free pothos?  Or is this not something I need to worry about?  

[Guppysnail]

This is a concern however easily remedied. I take clippings from the mother plant and allow them to root in the tank. I found placing dirt grown roots in tanks not to work. The dirt grown roots disintegrate as it grows roots adapted to grow in water. 
I take the clipping and spray original Dawn dish soap and water solution on the clipping and rub gently with my fingers. Then rinse very well under cool water to remove all residue. Original Dawn rinses clean.  
Here is a thread you may enjoy about other plants that do fabulous for nitrate removal and look amazing. 

 

[Epiphanaea]

Thank you!  I ended up getting a monstera (for the well-being of the fish, you understand - definitely not because I’ve wanted one) and washed as directed.  🙂

[Guppysnail]

I grew out a giant monstera and took cuttings for all my tanks “strictly for nitrate control”🤣 as well  😉 

[Maximus]

On 8/2/2023 at 12:43 PM, Guppysnail said:

Original Dawn rinses clean.

Is this referring to the non-concentrated liquid Dawn? All I can find is the concentrated stuff, but it also seems to rinse clean (just need to use less).

[Guppysnail]

On 8/3/2023 at 11:35 AM, Maximus said:

Is this referring to the non-concentrated liquid Dawn? All I can find is the concentrated stuff, but it also seems to rinse clean (just need to use less).

Concentrate is fine just not the powerized or scented stuff. 

[dasaltemelosguy]

On 8/2/2023 at 12:31 PM, Epiphanaea said:

I have seen lots of recommendations that having pothos growing out of your aquarium will help keep nitrites and nitrates down.  Where do you get pesticide-free pothos?  Or is this not something I need to worry about?  

Hi @Epiphanaea and @Maximus,

The pesticides commonly used on commercial pothos plants are thiabendazole and phosmet primarily. These chemicals are only soluble in water at a pH of 2 & 4 respectively.

As they are acidic, the most effective way to remove them is to immerse the pothos in an alkaline solution. This precipitates the thiabendazole, and converts the phosmet to a water-soluble phosphate so both of them will then rinse off easily.

@Guppysnail is correct about Dawn. It works, not only due to its surfactant qualities but even more so, because it's pH is about 9 or quite alkaline. 

However, baking soda may be preferable due to its low toxicity and ease of removal. Baking soda is also the most efficacious method advised by the EPA. Baking soda will remove about 96% of the phosmet and about 80% of the thiabendazole. Unfortunately, about 20% of the thiabendazole penetrates the leaves and will never come out. But as it is insoluble in water at a pH that fish require, it’s also effectively not toxic.

A simple, 15-minute bath in a baking soda solution will achieve this. 2 tablespoons of baking soda per quart of water is an effective solution. Soak the pothos for 15 minutes and rinse.

The EPA and many agricultural entitles have published studies comparing various cleaning and neutralization methods. Some advise using vinegar or bleach. Vinegar is ineffective comparatively and bleach is good but not as effective as baking soda.  Baking soda tops the efficacy list.  Here’s a just couple of links about this:

EFFECTIVENESS OF SODIUM BICARBONATE IN REMOVING PESTICIDE RESIDUES IN – The Green Boutique Zero Waste

Effectiveness of Commercial and Homemade Washing Agents in Removing Pesticide Residues on and in Apples | Journal of Agricultural and Food Chemistry (acs.org)

This may not be relevant, but the other toxin of infamy is the oxalate in pothos. You’ve no doubt heard of warnings that this may leach into the aquarium. However, the oxalates in pothos are only soluble in water at a pH of 4.5 or lower so it’s effectively non-toxic. You may even test this yourself with common, urinalysis test strips as they will reveal if any oxalate has entered the water column. It’s described here and these oxalate test strips are shown here as well:

Poison Pothos! - Plants, Algae, and Fertilizers - C.A.R.E. (aquariumcoop.com)

 

Speaking anecdotally, the tanks below had pothos in them for about 3 years. There are 12, large pothos plants here and admittedly, I only rinsed them with plain water before using them in my tanks without incident. Good luck.

[Chick-In-Of-TheSea]

On 8/3/2023 at 1:15 PM, dasaltemelosguy said:

I only rinsed them with plain water before using them in my tanks without incident

Same here.

[Epiphanaea]

On 8/3/2023 at 1:15 PM, dasaltemelosguy said:

Hi @Epiphanaea and @Maximus,

The pesticides commonly used on commercial pothos plants are thiabendazole and phosmet primarily. These chemicals are only soluble in water at a pH of 2 & 4 respectively.

As they are acidic, the most effective way to remove them is to immerse the pothos in an alkaline solution. This precipitates the thiabendazole, and converts the phosmet to a water-soluble phosphate so both of them will then rinse off easily.

@Guppysnail is correct about Dawn. It works, not only due to its surfactant qualities but even more so, because it's pH is about 9 or quite alkaline. 

However, baking soda may be preferable due to its low toxicity and ease of removal. Baking soda is also the most efficacious method advised by the EPA. Baking soda will remove about 96% of the phosmet and about 80% of the thiabendazole. Unfortunately, about 20% of the thiabendazole penetrates the leaves and will never come out. But as it is insoluble in water at a pH that fish require, it’s also effectively not toxic.

A simple, 15-minute bath in a baking soda solution will achieve this. 2 tablespoons of baking soda per quart of water is an effective solution. Soak the pothos for 15 minutes and rinse.

The EPA and many agricultural entitles have published studies comparing various cleaning and neutralization methods. Some advise using vinegar or bleach. Vinegar is ineffective comparatively and bleach is good but not as effective as baking soda.  Baking soda tops the efficacy list.  Here’s a just couple of links about this:

EFFECTIVENESS OF SODIUM BICARBONATE IN REMOVING PESTICIDE RESIDUES IN – The Green Boutique Zero Waste

Effectiveness of Commercial and Homemade Washing Agents in Removing Pesticide Residues on and in Apples | Journal of Agricultural and Food Chemistry (acs.org)

This may not be relevant, but the other toxin of infamy is the oxalate in pothos. You’ve no doubt heard of warnings that this may leach into the aquarium. However, the oxalates in pothos are only soluble in water at a pH of 4.5 or lower so it’s effectively non-toxic. You may even test this yourself with common, urinalysis test strips as they will reveal if any oxalate has entered the water column. It’s described here and these oxalate test strips are shown here as well:

Poison Pothos! - Plants, Algae, and Fertilizers - C.A.R.E. (aquariumcoop.com)

 

Speaking anecdotally, the tanks below had pothos in them for about 3 years. There are 12, large pothos plants here and admittedly, I only rinsed them with plain water before using them in my tanks without incident. Good luck.

You are awesome.  I wish I had known this *years* ago!