Quagga Mussels in Black-water Tanks

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Aside from engine cooling water, our houseboat has only two lake water intakes for each of the marine heads and I am concerned about the possible damages that Quagga Mussels could do to that system. I've been doing quite a bit of research, but I can't find anything definitive on whether these mussels will cause problems in the black-water tanks and, if so, what the best option would be to prevent that damage. I know that chlorine will kill veligers, but I can't introduce chlorine to our holding tanks without killing our enzyme based toilet treatment and that wouldn't protect the supply pump or lines to the toilet.

My thought was to add a UV sterilizer to each intake, but I'm not sure that it will completely kill off the veligers. This study, though it advocates multiple treatments with the UV sterilizer, looks to me like after 96-hours 1-treatment has greater then 90% mortality rate for the veligers and I would guess the remaining mobile veligers would not be healthy.

I guess my next step is to contact some UV sterilizer manufactures and see what they say regarding mortality rates for veligers, but I thought I might post here and see if anyone had any information or had already installed something similar.
I think this whole thing is going to be a long, painful, and expensive learning process. I am still surprised and disappointed about the lack of information out there.
What about a filtration system at the intake? Seems you would have to sterilize and replace the filters, but at least it would minimize the amount of lines and systems that could be infested.....
What about a filtration system at the intake? Seems you would have to sterilize and replace the filters, but at least it would minimize the amount of lines and systems that could be infested.....

I was thinking of putting the UV sterilizers at the intakes, powered when then pump is running. I considered filters, but I believe that you need to get down to 20-microns to exclude veligers and I worry about such a fine filter clogging and needing continuous replacement. I need 3-gpm flow rate for the head systems and I was thinking, if UV is effective, it should allow for virtually unrestricted flow. I may have to look at filter options again.
there is a filter system on the market for the wakeboard boat ballast systems, they are coming with certifications and filter tags that the powers that be are accepting as quagga free, you can wakeboard at Powell one day and bear lake the next. I cannot remember the company's name, but maybe add these filters to your intakes and service yearly. im thinking the name was wakeworks or musclebusters, something like that
A 20-micron filter will flow fine. Some years ago, I was having problems with suspended silt in the lake water taking a toll on toilet flush valves and other faucets. I installed a 5-micron filter and it solved all the silt problems. I haven't had to replace a toilet flush valve or rebuild a faucet since.

Like you, I was worried about flow rate and filling the filter too fast. To solve what I thought might be issues, I installed a 4.5" diameter by 10" filter housing. Water guys call that a "Big Blue." A single filter element would last all season and had great flow rates. Trouble was, dirty lake water sat in that housing between trips with summer temperatures between 80 and 100 degrees. It got stinky. I thought about installing a new filter element each trip, but the Big Blue filter elements were $6 or $7 each and a little messy to change.

At the start of last season, I took out the Big Blue housing and installed a standard (about 2.25" by 10") filter housing that takes 5-micron elements that are under $1.50 each. I installed a drain in the bottom of the housing to make it easy to drain and replace the element each trip. I was a little concerned about flow rate with the smaller filter, but that hasn't been an issue at all -- even at 5 microns. If I ever do have an issue, I won't hesitate to toss an old filter element and put in a new one. After all, they're $1.50 each.

For what it's worth, I bought my stuff at Fresh Water Systems. My filter housing is a Pentek 10" 3G Slim Line Filter Housing Black/Blue MB w/ PR that goes for $12.27 in the 1/2 inch pipe size. Part Number: 158621. I had to drill, tap, and JB Weld a 1/4" by 1/8"brass pipe bushing in the bottom to accommodate a 1/8" drain valve to make the housing easy to drain to replace the element. Link: https://www.freshwatersystems.com/p...im-line-filter-housing-blackblue-mb-w-pr.aspx

The filter elements I use are Neo-Pure MB-25098-05 9-7/8" Polypropylene Sediment Depth Filter 5 Mic. A 50-pack is $72.18. Part # MB-25098-05:50PK. Link: https://www.freshwatersystems.com/p...olypropylene-sediment-depth-filter-5-mic.aspx

With the luck I have had at 5 microns, I am confident in saying you will have no issue at all at 20 microns.
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Thanks for the responses, I think that a filter might be the most economical route. If you haven't had any issues with clogging up filters at 5-microns, I think we should be alright.
Just wanted to update this; before we relaunched I installed the 10-in filter housings @Endurance mentioned on both of the lake water intakes for my heads. It seems like our boat is going to get enough use that there probably won't be too much time for the water to get ripe. We'll see how they work this season.

University of Michigan has the most info on Quagga/Zebra Mussels. They are experimenting with a species of Perch which eats the mussels, but won't go deeper than 10'. The mussels have been in the Great Lakes for many years. The Zebras are the worst, leaving big shells all over the place, cutting the kids feet. Some outdrives in the Traverse City Marina are balls of mussels.
We disconnected our filter years ago because of the smell. A cup of bleach after each pumpout takes care of our black water tanks. We brush off the area around our lake water intake each trip to the lake. I replaced a pump last year and found no mussels in the pump or tubing.
Thanks, @Jim Morgan, is your boat at the North or South end of the lake? I think the mussels were just getting a foothold at the North end last year, but will likely be mush worse in years to come. Out boat was only in from June to November last year at Bullfrog and I found mussels in the out-drives when I did an impeller replacement last month before relaunching. We use the enzyme toilet treatments and our marine heads have a lot of rubber parts that are not Chlorine compatible. I'm hoping that our boat is going to get regular enough use to keep the smell from getting too bad, but we will see.

As to the perch, I'm hopeful that a solution will be found to deal with the mussels. In another thread, Wayne mentioned that the Bluegill may be proving to be happy molluscavores and they're looking at redear sunfish as a potential addition to help keep the mussels in control, but neither of these will eradicate the mussels.

I've read a lot about a treatment called Zequanox, which is a microbial molluscicide that kills the Zebra and Quagga mussels without impacting other species. It was approved by the EPA for open water use, but as I understand it the cost is too high for treating a lake the size of Powell, or really any good size reservoir. Additionally, if you were to kill off all the mussels in Lake Powell, the dead mussels decomposition could create an anaerobic environment that would kill off other species. If the filters don't work out, I will look at this as a possible additive to mussel control in our tanks.
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