I am amazed at how little fouling there is on my boat 2 years after the last slip in December 2020, when I applied 3 coats of Altex No. 5. Today was the first time I had given it a wipe (with a soft broom), and it all came off very easily. There was very little in the way of hard growth.
I normally shoot for 2+ years between slips and after 2 years in the past it's often gotten pretty ugly, but this time I'm very surprised. I expected a lot of growth due to the incredible amount of nutrients (ie dog poo etc) that must have been flushed down by the La Nina rains.
Do others have similar experience, or has Altex suddenly become supernaturally effective? Or is there a secret lethally toxic discharge somewhere up the Sandringham storm water drain?
Cheers, Graeme
Hmm..l antifouled in September and by Christmas the diver charged me extra to clean it. I was surprised. St Kilda.
That was just micron tho. Maybe next time l will use altex
I have Altex No5 plus to go on shortly. I have found it's pretty hard to predict how long antifoul is going to last. There are so many variables. I reckon all the extra rain this year though has probably helped more than hinder. Warm fresh seawater with plenty of current flow and sunshine is what gets all those little pesky bugs going.
That's a good question, Graeme. I've also noticed a change...
I've been using Altex 5 for years - I think it is a good product. I regularly get 15 to 18 months per treatment. I'm at Parsley Bay, on Hawkesbury.
Anyway, i last anti-fouled in March 2021. Currently, there's no growth at all, just the usual later of slime. So, it's almost 2 years, and I think I can safely stretch it another six months. One wonders if they have 'tuned' the formula?
A Resene rep once told me that 5 Plus has more copper, no other difference. He said that one could tweak 5 by adding cuprous oxide - available on ebay. But, I'm no industrial chemist, so I was reluctant to try a diy mod. I think anti-foul paint is a bit of a black art, so I'm always amused to hear about the so-called magic fixes - eg adding pepper. 
I've used Altex 5 a couple of times before and it wasn't as good as this. Maybe they've "tuned" it as you say, or as Ramona says maybe the fresh-water dilution has an effect. Either way I'm pleased.
