I am running 525 EFIs with Sportmasters, low water pickups, and we run in a lake with a sandy bottom but occasionally see some seaweed in other lakes. Are sea stainers necessary for my application and if not when would I need them in relation to water conditions?

imo every boat should have them.

I ran Lake Michigan and some rivers for many many years without them and never had a problem. However after recently seeing a couple of blocks that had enough sand etc in them to litterally put a good start on a kids back yard sand box - I would never run without. Sure the said boat ran some shallow water for a short distance every time in and out however it was unbelievable. Can cause hot spots and poor cooling at least in the 454's. Regardless I went and bought two shortly there after what I saw. Not good. Cheap insurance and easier on impellers. Just my 2 cents

I agree, I think they are cheap insurance. compare price of new motor to a sea strainer.
sure not needed, I was surprised that my 340 sea ray doesn't have them,,,but............
imo...............

Look at it this way, it won't hurt and when you add them it's easy to put a flush kit in at the same time.

Most don`t anything for stopping sand. I tend to get too close to shore and pick up sand. I haven`t figured out a way to flush it out yet.

I agree.

I am not going to say IMO - I am saying they are a component that should be installed from the get go.

Just a side note - I can not recall a wakeboard boat without one in many years. Of course they do not use the bigger offshore style strainers but just making a point as that's one line of boats sea strainers come installed, day one from the boat manu. and there is reasons for it.

IMO they are important to have and double important to have especially if you do not have close cooling.

Never had a strainer in any one of my boats for over 25 years and never had a single issue,I will be installing them in my newest build due to pulling water from the surface.

Like I mentioned in earlier post I didn't either. 30 plus years of boating. Well maybe one had them. However even new boats I've purchased didn't have them. Lot has to do with where you boat conditions etc. I'm not kidding when I say wheat I saw come out of these blocks that I witnessed. Litterally flipped blocks over on engine stands and was amazed and then started with the plastic hammer. Unreal. They were not mine however I do boat in same area. I've got way to much money into engines not to have them. I searched for a couple new used ones here on OSO and glad I did. Think I paid 450.00 for both. One of the cheapest things I've ever purchased.

Engines i brought up with issues was more so a soot and chewed up seaweed with a blend of sand. Most my own boating conditions probably would not be necessary but again why not?