AngerMgmt

NuHull....works great. I think it's muriatic acid. Spray on and rinse off.........or heavier spots my need a light sweep with a soft brush. Something like $40 a gallon which will do a 30' boat atleast a dozen times.

Audiofn

Got to be carefull with a lot of this stuff if you have and alluminum or galvanized trailer.

VOLS29outlaw

i use works toilet bowl cleaner, put it in a pump up spray bottle mixed with water and it works great dont even have to wipe it off just spray it off.

JB33

I am on the mississippi also and used to clean many boats in the fall. Muratic acid never fails. pump sprayer and pressure washer.

I had to do lots of boats and always removed them from the trailer due to the acid eating paint and metal. Its really nasty stuff, respirator and gloves are a must.

You may want to check out the other options first.

ozarkdevil

I live on the muddy Mississippi also and after a couple long weekends out on the water I will clean with slimy grimy. 1 table spoon (powder) of grimy in a gallon spray bottle & that stuff works great. Enviromental safe, no gloves just spray on.

fossil fuel

Oxalic from west marine in powder form. cheap and safe. Cheap garden sprayer
Keep the hose going on the trailer when you spray the hull.

pluguglyinhere

I had a similliar thread and asked around at the lake. We have a muddy lake and I would have coffee stains from the water line down. It was not just a line but like I put a brown graphic on the boat. I used toilet bowl cleaner, Works and it did work excellent. I then as many told me too, polished the boat with a mild polish, then two coats of a GOOD wax. I know only have to remove a brown water line with a diluted toilet bowl cleaner/water mix. I am happy

Dd24skater

Lemon Juice in a spray bottle works for me

Dr Ralphy

I have the same problem at our local lake. Mud stains get in the glass after a few days on the water.

I use Muriatic or Hydrochloric acid in a spray bottle or a brush on a stick. Takes it right off with no elbow work. You need to be careful not to get it on aluminum! And make sure to rinse very well after including the trailer.

WildRooster

Muratic Acid is pretty strong stuff....a bit less "aggressive" but absolutely strong enough to do the job is a product that can only be found at Ace Hardware called Wood Acid. $8 a bottle and mix with 2 gallons of water. Then pour into a good industrial spray bottle. Bring it out every few washes if you start getting the hated brown water line. Just spray on, watch it for about 5 seconds and rinse off. Just to be absolutely safe, I come back over it with a brush n soap to make sure I get it all off. Works great and cheap!!!