Bats and borates

[keezer]

Hi all,

Long-time lurker -- I love this site! A cursory search of TFP has always been enough to answer any possible pool-related question, but I finally came up empty on a something that's admittedly pretty out there...

I'm about to embark on my first replaster (Wet Edge Signature Matrix) and am contemplating incorporating borates into my water chemistry after completing the new plaster start-up. In looking into the use of borates, I think I understand the normal considerations (i.e., not good for dogs that drink excessive amounts from the pool), but does anyone have any idea about harmful effects on bats that drink from treated water? I live in a very wooded area and have a number of bats that visit the pool to drink water -- I'd hate to poison them since they're so handy for eating mosquitoes.

I can't find any sort of research on the subject (since hopefully no one's conducting research into trying to poison bats, I guess), but was curious whether other pool owners who maintain borates at the normal ~30-50ppm level could share whether they still have bats that visit?

 

[BenB]

You sent me down a Google black hole!

Per Wikipedia, the LD50 of Borax is 2.66g/kg in rats. A bat is fairly similar to a rat - after all it's just one letter different (ok but I don't really know if this is true - but they are both small mammals).

Per the North Carolina Bat Working Group, the first entry on their list of common NC bats was the Big Brown Bat. They say the Big Brown Bat has a weight ranging 11 to 23 grams.

Based on the lower weight then, let's say the LD50 for a typical bat of that size would be a dose of 0.03g of borax.

50 part/million (ppm) of borates is equal to 0.05 gram/liter. [I did not consider any molecular weight differences for 'borates in pool water' vs. borax - I have assumed when we talk about 50ppm borates, that is the same weight as the full borax molecule and not an ion. Far smarter chemists can correct me on this part!]

Therefore, at that concentration in pool water, a bat would need to drink 600ml (0.6L) (20oz) of pool water in order to have a 50% chance of killing it. That isn't a lot of water, but it's 55x the bat's own body weight. So probably more than it can drink in any reasonable length of time!

That's probably enough for me to conclude that borax in pool water is not harmful to bats. Yay!

 

[revitup]

Boom!

 

[kellyfair]

 

[mgtfp]

Now that your thread is up and running, TFP is suggesting in the "Similar Threads" below your thread an older thread called "Borates and bats":

Borates and bats

I love the bats that live in our neighborhood and help eat the mosquitoes in particular. Last summer they moved, but the colony is thankfully back this year. I know that borates are not good for dogs to drink the water from the pool. The bats skim our pool nightly for water; are my borates at...

www.troublefreepool.com

Conclusion seems to be the same. And good luck with your replastering!

 

[keezer]

You sent me down a Google black hole!

Per Wikipedia, the LD50 of Borax is 2.66g/kg in rats. A bat is fairly similar to a rat - after all it's just one letter different (ok but I don't really know if this is true - but they are both small mammals).

Per the North Carolina Bat Working Group, the first entry on their list of common NC bats was the Big Brown Bat. They say the Big Brown Bat has a weight ranging 11 to 23 grams.

Based on the lower weight then, let's say the LD50 for a typical bat of that size would be a dose of 0.03g of borax.

50 part/million (ppm) of borates is equal to 0.05 gram/liter. [I did not consider any molecular weight differences for 'borates in pool water' vs. borax - I have assumed when we talk about 50ppm borates, that is the same weight as the full borax molecule and not an ion. Far smarter chemists can correct me on this part!]

Therefore, at that concentration in pool water, a bat would need to drink 600ml (0.6L) (20oz) of pool water in order to have a 50% chance of killing it. That isn't a lot of water, but it's 55x the bat's own body weight. So probably more than it can drink in any reasonable length of time!

That's probably enough for me to conclude that borax in pool water is not harmful to bats. Yay!

That's quite a Google black hole! Thanks for posting those findings -- solidly reasoned (especially the part about bats and rats)!

Given the ludicrously high amount of water a bat would probably need to drink, I think I can move forward with using borates without needing to worry about my furry flying friends. Looking forward to some sparkling, balanced water!

 

[dajcadams1]

I maintain around 40ppm, and have bats around the pool every year.