The Outdoor Line Forum

Here's a question for scientific crowd. So recently Lake Stevens was treated with Aluminum sulfate for the algae bloom. Does anyone know how this effects metals and their voltages in water? I ask because earlier this spring I went through my boat and cleaned up all my connections and check my voltage on my stainless downrigger wires. I saw about .7 volts after some zinc tweaking. Now, last night I checked randomly and I'm seeing around 1.01volts. Nothing has changed on the boat, except its seen some extended saltwater use. All the zincs are scrubbed.

Could that aluminum sulfate be creating an increased electric field? ie, making a better battery? Just curious if anyone else has ever noticed the same thing with regards to the aluminum sulfate or if possible I just have a new electrical leak.

How did you scrub your zincs? Did you use a steel brush by chance?

Always a stainless steel bristle brush followed up by a nylon bristle brush

I would go through your boat and turn on each electrical device one at a time, and test your lines each time you turn on the device. It could be that maybe you don't have enough zinc. This is a tough problem to chase down. You could try testing the water and compare it to another fresh water source. Another quick question, are you testing this while the boat is on your trailer or while it's in the water?

Here's the real kicker. When I measure the voltage from my hull with no batteries hooked up at all, I still get around 1 volt to the downrigger wire. As I go back and reconnect everything the voltage comes up like .1volt. I'm really beginning to think this aluminium sulfate change the alkalinity or something like that of the water. Either that or someone slipped me some monel downrigger wires. Anyone ever measured the voltage on those wires?

Mitch-
When were you on Stevens? Was it near the time of the "treatment".

I could see the alum treatment (55,000 gallons of material was sprayed over the lake surface in a 3 day period) having a short term effect. However the material "binds" with the nutrients form snow like particles that drop to the lake bottom which occurs over a several day period. After a few days I would not expect the treatment to be the cause of voltage issue.

Curt

Hey Mitch,
I think you've "killed" your zincs. The only way I clean them these days is with a pressure washer at close range.

I used to keep a wire brush specifically for my zincs, using it for nothing else since other metals, placed on the surface can, essentially "neutralize" a zinc.

Now I pressure wash them a couple times a year and replace them every year.

To your question of Lake Stevens treatment of heavy metals, it would take a major, toxic amount to significantly change the salinity of a fresh water lake to the point it would manifest itself in the voltage issue that you're describing.

Good luck!

Smalma,
It was 3 days after they sprayed the lake. However, my boat was in the lake for about a week prior and during the spraying? I always thought my voltage would drop the longer the boats sat in freshwater due to the zinc becoming inefficient. Not the other way around.

I have 2 zinc's welded directly to the hull and another grouper zinc grounded directly to the negative battery terminal when I leave it in the water. The grouper zinc does not touch the hull at all.

I'm beginning to think it may be monel wire throwing me off

However, because of the problem of electrolytic action in salt water (also known as Galvanic corrosion), in shipbuilding monel must be carefully insulated from other metals such as steel This would also apply to your monel downrigger wire also.

Stainless cable transmits electricity. As stated in the previous bullet point, this can be good or it can be bad. If you use a black box such as the ProTroll model or the Cabella's model, cable can serve a purpose allowing you to send out the proper electric charge to actually attract fish. You can also help to keep the negative effects by maintaining the sacrificial anodes on your motor and hull.

Braid has a thinner profile than stainless steel cable. Because of the thin profile, you will experience less blow back (water resistance) keeping your downrigger weights in a more vertical position when trolling at depth.

anything beyond this information on wire will take an Electrical engineer to clarify or give more and better information