Larvae or bugs in water. Question on what they are and what to do about it.

[magicclaw]

I have these larvae or bugs in my water. My wife is convinced they are a nymph/larval stage of dragonflies and rescued a ton of them yesterday to transplant to a nearby pond. I’m concerned about (a) what they actually are (if dragonfly or not) and (b) how/why they are suddenly growing in number and thriving in my pool.

Here is a video I took of the bugs/nymphs we collected yesterday evening:
Water bugs — boatmen? dragonfly nymphs?

I’m keeping my FC levels where they should be (generally…I have the occasional miss where I let it get to the lower end of the pool math recommended range, but I am generally quick to catch it back up). I know my CYA levels are higher than they should be, but I am following the recommended FC levels for my CYA according to Poolmath, and anytime I’ve done an OCLT, I have never seen a loss of more than 0.5~1ppm of FC, indicating the pool is functioning properly. Similarly, I generally get a zero on CC, with only a very occasional reading of <=0.5ppm.

I appreciate any help!

Final additional context:
Hello! Yes I know this is my first post. Sorry for such a huge first post! I’ve been lurking here for awhile; I took over managing my pool according to the “TFPool way” back on July 1st of this year. Using a TFTestKits TF100 for testing this whole time. I really appreciate what a great resource this and the Poolmath app have been; I’ve learned a lot going through the forums and all the materials in Pool School!

Regarding this issue, I want to say up front, yes, I have searched and read other posts re:boatmen / backswimmers, and I’m guessing my next order of business may be to go ahead and slam the pool if these are indeed boatmen to ensure we have killed any festering algae. We also have a bunch of boric acid on hand as we were going to start running the 50ppm borates in the pool, but we haven’t actually dumped them in yet. It sounds like maybe that might help too with these bugs?

Finally, my Poolmath pool link:
PoolMath Logs

My pool is located in NW Houston, TX.
Also, FWIW, the pool is supposedly 13000 gallons according to the original contract/work order (previous owner was nice enough to provide that), but I have Poolmath’s settings set to 17k because that seems to give me better outcomes with recommended liquid chlorine and muriatic acid additions.

I need to set up my sig still, sorry, so I’m having to add a bunch of extra contextual info here.

Edit: added a current photo of the pool taken just a few minutes ago.

 

[magicclaw]

Okay. My wife is now in agreement that they are not dragonfly larvae/nymphs and feeling somewhat silly for having spent all that time “saving” them yesterday lol.

So my question now is more along the lines of…why are we having this explosion? The pool looks/seems clear. We keep the chemistry balanced. I run the pump 24/7: 17 hrs @ 850 rpm, 2 hours @ 1600 rpm, 4 hrs at 2600 rpm, 1 hr at 1000 rpm.
The pump schedule above is something I set up near the end of August. Previously it was running at 1200 rpm most of the day with 4 hrs at 3450 rpm.

So, I’m wondering if the problem is related to the lower pump speed combined with the sustained lower temps we have in the pool now that the heat of summer is leaving us. At least, the cooler water and lower pump speeds being why we are seeing the large influx of backswimmers. As to why they are flourishing, I would have thought any algae would have been most active when the water temps were warmer, and would have shown up when I have done previous OCLTs.

I have never done a SLAM before. I have not seen a need to based on the readings I’ve gotten. I’m not excited about having to do one now, and my readings already match the desired levels needed to complete a SLAM. So I’m not sure what to do there. I suppose I could just do a 24 hour (or similar time-bound) SLAM level of chlorine regardless of readings. But I feel I need to do something. We have never seen these bugs in such large quantities before. We saw them occasionally when the pool was being maintained by a service, but not like this.

 

[magicclaw]

So I feel like I’m just talking to myself / spamming; sorry. I don’t mean to be overly verbose. I just figure I will keep this up to date though pending any input/feedback from the forum members.

My wife started our pool robot on a cleaning cycle and I went ahead and manually set the pump to full speed (3450rpm) for the next four hours. I am still undecided whether/how to proceed with any SLAM, but figure I will wait until this evening, and will just get my pH levels prepared in the meantime.

 

[Mdragger88]

What is your cya? The last log for it was 2 months ago.
As for why are they congregating in your pool- who knows- sometimes it just happens with a giant inviting open body of water in your backyard. You mentioned a pond close by. May not be anything you have done.
Keeping fc elevated should deter them from proliferating.
When they are small its hard to tell if they are backswimmers or boatmen. Either way crank the fc up and scrub everything down.
Have you done an oclt since you saw them? If not, its a good idea. Then you will know if you need to do the
SLAM Process or just elevate the fc for a bit.
*While cold water (below 60 degrees) inhibits algae’s growth it doesn’t make it impossible.

 

[magicclaw]

I will do another CYA check. It generally doesn’t fluctuate much so I stopped testing it as regularly. If anything it tends to go down as I occasionally overfill the pool when doing refills

I will do an OCLT tonight as well. I just put in some more chlorine that should get me up to around 9ppm and enough acid to bring me down to ~7.2 pH for the rest of today.

 

[Rancho Cost-a-Lotta]

As mentioned, it's hard to identify them through the video. Look up "springtails" and compare. If you identify them as springtails, do a search here. There's not a whole lot you can do, but they are harmless.

 

[magicclaw]

Definitely not springtails.

I just fished one out and took a photo with my phone. Short of getting out my “big camera” with a macro lens, this is probably about the best close-up photo I could get.

 

[magicclaw]

So, if anything, my CYA levels are lower. I hate the CYA test because of the subjectivity of ambient lighting affecting how well the little dot can be seen. But I’m pretty sure my reading came up at roughly 50ppm now, down from 60ppm previously.

I now have FC up to the upper bounds of the Poolmath recommended normal range. It measured 9ppm earlier, and then 10ppm on my most recent test. Seemed odd that it increased between those tests; my only explanation is perhaps the pool wasn’t mixed fully before since I had not increased the pump speed after adding my most recent batch of chlorine, but then did turn it up in the past hour and a half (so we could use the skimmer port hose to vacuum up a bunch more bugs).

Now to wait until morning to see what the OCLT says.

 

[Mdragger88]

Thats a backswimmer.
They can bite so be careful- you may wish to unalive them after extraction rather than rescue/relocate them. Sucking them up is a good idea as I assume they will drown.
They are predators that eat other insects like water boatmen who eat algae among other insects.
Their presence doesn’t automatically mean algae but it is a good idea to confirm you’re algae free & if not proceed with slam.
Pest control around the pool can be helpful in controlling unwanted insects in the pool.

 

[magicclaw]

Yeah I did a fair bit of additional reading yesterday and learned more about the boatman / backswimmer relationship and realized we have some of both. We definitely are not saving them anymore. They are marked for death lol. Or at least eradication.

My OCLT result didn’t indicate a particularly active chlorine consumption issue; the reading this morning just before sunrise was 1ppm lower than my final reading the night before. Even so, I went ahead and began a SLAM today, bringing the levels up to 20ppm and checking/adding at midday and this evening. Dang if this process isn’t gonna run me out of DPD/FAS reagents in no time; I placed an order for more today…

So, thanks for the feedback and suggestions everyone. I think at this point the best I can do is what I’m doing; I figure I will maintain the SLAM levels and keep brushing the pool through the weekend and see if things calm down from there. Definitely saw fewer of the little buggers so far today. Not zero, but fewer.

 

[Mdragger88]

I hope they go away!! Very annoying when pests find their new home in your pool!
I have a pond behind my house & get some interesting visitors- including backswimmers and water boatmen on occasion.
Mo chlorine lol!