Hard Bottom/ Dents Already?

[CJDahl]

I just installed a 28x45 Free Form in-ground/steel construction vinyl liner pool. I went with the "hard bottom" option for about $1000 extra which I understood was suppose to prevent dings and dents at the bottom of the pool. We went swimming for the first time yesterday and I immediately felt two (2) small craters approximately 6" wide and perhaps 1/2" deep on the bottom of the pool under the vinyl liner. From what I can sense it feels more like sand in these areas than "hard bottom". So far I am extremely satisfied with my purchase. Is this to be expected with "hard bottom" or should I complain to Pool Company? Thanks in advance for any advice .

[Chardonnay]

A "hard bottom" pool can still get dents or indentations and will be especially vulnerable the first year you have the pool. But not to worry. It won't in any way "hurt" the pool. The main reason a "hard bottom" (vermiculite/purlite/zonolite) is superior to sand is because sand washes away when you have water behind the liner and a hard bottom won't.

If you really want to see something, turn on your pool light at night and look at the bottom of your pool--it will look like the moon. But again, there's no harm in it.

[CJDahl]

Thanks for response. I guess I was under mis-impression that vermiculite hard bottom would not dent. In fact I turned on my pool lights tonight and I did see yet additional dents and and indentations. Not the moon but definitely not the silkly smooth bottom I imagined a thousand bucks would get me. Bummer!

I should also mention that the very next day , immediately following the installation of vermiculite hard bottom, my pool company installed the liner. But on vermiculite web site it is recommended that there be no traffic in the pool until the vermiculite has had sufficient opportunity to harden.
"This period will normally be two days depending up temperature. Traffic in the pool prior to sufficient hardening will result in unsightly indentations."
Could the next day liner install have created these dents? It was about 100 degrees on the particular day of vermiculite install which perhaps would speed the vermiculite hardening process (??)

[webfeet]

CJ,
Glad you started this thread. Do you know if vermeculite, sand and cement are better than sand and cement alone for the bottom? I know the vermeculite and cement can be indented, but it is suppose to provide drainage beneath the liner. My pool builder wants to make the decision on which bottom to use after the excavation. The price is the same for either bottom. I am wondering if I should insist on one or the other.

[waste]

CJ, the floor shouldn't be dented, however there are a few reasons they do get dented. 1. Inconsistant mixes, ie not enough cement in certain areas, but whoever was trowling the 'mic' should have noticed it. 2. Soft spots under the 'mic', mud is notorious for this, any muddy soft spots should be dug out before applying the 'mic'. 3. Bad trowling, given the temp you describe, in a steel walled pool it's understandable that the 'human errors' will increase, but those should be patched before the liner goes in.
Given the temp, the floor should have been hard enough to walk on the next day. Talk to your builder and see what can be done about the dents (the only thing I can think to do is drain the pool, pull out a section of liner and have someone patch the bad spots - it'll be about 150 deg under that liner, a good incentive to do it right the next time, and it'll cost the builder some $)
Web, I don't like sand and cement because it's too hard, it can abraid the liner and won't let water pass through) Vermiculite gets very hard when it's fully cured (~27 days) especially with the weight of the water compressing it.
As Chardonnay (BTW welcome) -points out the liner has enough stretch that the dents won't hurt it, but for $1000, you should at least have a level area to walk on. - Waste

[CJDahl]

Thanks for the info Waste. While I am not happy about the dents at this point it would probably cost me another $1000 in water and chemicals just to drain the pool then refill (not to mention a family mutiny if I were to suggest this anytime soon after having waited so long for installation). Absent any other suggestions I guess I am left with trying to negotiate equitable financial settlement from builder.