sea swim advice - calf cramps

[plasticinemachine]

Hi all:) I have previously completed 2 open water swim events, one which was 2 miles and one which was 1 mile. They were both in the sea. I struggled on the 2 mile one, mainly due to not being able to swim breast stroke in a wetsuit - too boyant! I got awful cramp about 1 mile in, but managed to keep going & complete the race.
One the one mile race I bought my own wetsuit, much better and also practised my front crawl to at least alternate strokes on the swim. I did that but still suffered cramp towards the end of the race. As it was only 1 mile, it was so near the end I managed to float to the end!! This time the cramp went right up my legs and was very disabling. I did think Id have to bail even being so close to finishing.
So in 2 weeks I have this years charity swim! Its 1.4 miles & the regulations state wetsuits are optional! For me this is great, I can ditch the wetsuit & will swim in a swim skin instead to keep core temp, but should be much more flexible and allow me to swim some breast stroke without being awkward. Im hoping this will be the answer to my cramping issue, but obviously not 100% sure.
What else can I do to minimise my chances of cramps? The swim is at 10am. Usually I eat museli & banana for breakfast around 3 hours before swim & then drink bottle of sport drink plus energy bar half hour before.
Tips please? or comments on what I might be doing wrong!

[TriJo]

Cramps can sometimes be caused by low potassium - a banana and a bottle of water with a Nuun tablet or Dioralyte in it closer to your swim could help there. Are you a salty sweater? You may have sweated quite a bit into your wetsuit and lost a lot, particularly if you're having to work hard due to pretty much fighting the suit when swimming breaststroke or a stroke that is not your preferred one.

If you are anywhere in the south, I wouldn't bother with anything more than your swimsuit, one or two caps and goggles at the moment - inland water temperatures are borderline no-wetsuit (22c ish) for triathlon swims at the moment and you should be quite comfortable if you are reasonably well acclimatised.

I would consider trying to get an open water swim in this weekend in your race day gear - if there is somewhere near you with a marked loop course of 400-700m that would be ideal. You can experiment a bit and see what works for you.

[plasticinemachine]

Thank you that is great advice! I don't know if I'm a 'salty sweater' but I do sweat a lot (bit grim!) & yes I would say 'fighting the wetsuit' was exactly what the swims felt like! Well the swim is Bournemouth pier to pier & I checked water temp and it said 15 degrees currently! It was on a Bournemouth pier website, maybe a surf site. If the water is as warm as you say Id be very happy swimming without just my costume. I have no problem with cold water anyway & actually its one of the main things I like about open water swimming.
Thanks for the advice about a banana & water with the tablet:)