Ph Pen Questions

[aquarius]

I noticed that after closing my Hanna ph pen some water from the cap will come out. I thought it's ok as there will still be quite alot of water inside the cap to keep the probe moist.

After about 2 months when i opened the cap, i was astonished to see that its dried up! Luckily the pen still can be used but the inside has a black thing all over it. The white colour "brush" (not the transparent glass ball) is covered with this black thing. I managed to clean and rinse some of it off but the colour of the "brush" still looks abit blackish.

1) I'm wondering is that white colour "brush" important to the accurate reading of the ph pen?

2) I realised that you only need less than 1ml of water in the cap, anything more and it will come out. So how am i going to keep it moist all the time?

Please help and thanks.

[aquarius]

Can anybody help? Thanks