I have tiled sealed and grouted a shower floor area and the grout has seeped lower in some areas than I want can I overgrout. Any tips

sounds like it may have been overwatered. I'd rake some out and re grout so the next batch has room to sit in.

Be careful not to over water.

overgrouting will probably result in it drying an uneven colour, best to rake it out and ensure new batch is mixed to the correct consistency, when you turn your bucket trowel upside down it should stick not drip off

Graeme
ETL Pro Tiling

Did it drop after it had dried? It could be that you skimmed over the top of the joint without filling it completly, when it drys it would have cracked and dropped, or maybe that you washed the grout off before it was ready and pulled some out of the joints. Or as Trumpers said it could have been over watered.

yes I think I may have washed off too vigouously, to early and I think it may have washed some out then as well as a bit of seepage

You havnt said how big the floor is. If its not a big room I would cut some of the grout out (all the loose stuff) with a Fein multi master if you have one, if not a grout rake, sweep clean, wash with clean water to remove all dust, let that dry then mix up a new batch of grout and re-grout the entire floor, make sure you read the back of the bag as it will tell you how much water to mix it with and how long to leave it for before washing off.

Not leaving the grout to set up and washing off to early can result in low grout joints..

So can your coverage of adhesive if it has voids to run into, you'd want a uniform depth you can go to, even if its only 2 or 3 mm, so rake back and go over the whole floor.

I would rake it back and re-grout, raking it back so as you get an average depth all over off at least half the tile thickness to give you uniformity in colour of the new grout and it will give it a good key to stick too, i would also get a damp sponge and wipe over the old grout before you put the new in. only dampen it dont soak it!

thanks for the tips guys I have scraped some of the tile grout and it is as tough as old boots so I think I washed some out too early. I will scrape the whole area down 3mm and regrout after wetting

I'd take it down a bit more than 3mm