Families complained a waterpark attraction was overcrowded and pools turned green while they swam.
Visitors to Waterworld in Stoke-on-Trent also claimed changing rooms were left in a "disgusting" state - with some saying they were surprised by the state of the place even after the coronavirus pandemic.
One review read: "After lockdown happened I thought the whole place would have been cleaned but went today it was so busy and the water was green."
The colour of the water was queried by a number of customers, who mentioned "weird green water", reports StokeonTrent Live.
Several complained about the queues for the slides and outside and a 15-minute wait for a changing cubicle.
There were also issues with locker availability, again, due to the numbers of people on site.
Waterworld boss Mo Chaudry responded after a raft of reviews posted since the popular attraction - rated as 3.5/5 and and the 28th out of 102 things to do in Stoke-on-Trent - were critical of his business.
And he called on sites such as TripAdvisor to "weed out non-genuine reviews and trolls".
Mr Chaudry said: “To suggest that our venue is overcrowded, unsafe or unhygienic is quite simply inaccurate and irresponsible. The facts tell a far different story.
“We have also extended daily opening times by two hours to 7pm to help distribute customers more evenly – at significant cost to ourselves – simply because we want people to have a great time.
“We have a substantial number of lifeguards and pool attendants on duty to ensure pool safety.
“Nearly all customers now book online, and the introduction of half-hour time slots mean waiting times are dramatically reduced. We also have robust procedures in place to manage their three-hour time limit on site.
“Our pool water is stringently and regularly subjected to microbiological tests, where zero health and safety risks have been revealed."
“As for customers commenting on the green tinge - we sell ourselves as a tropical environment, and believe green is good! Much of our water comes directly from a highly eco-friendly borehole on our own site."
“The Waterworld resort is looking the best it has ever looked. As part of a £12 million investment, we have extended the park with four huge new rides, upgraded the poolside, added over 1,000 new digital lockers, plus more cubicles, more showers and more toilets.
“It is time for online review platforms to take far greater responsibility for fact-checking the comments they allow to be posted and shared, and to weed out non-genuine reviews and trolls.
“We’re not perfect, but it's important to put this small number of comments into perspective – since reopening in May we will have welcomed more than 150,000 very happy customers by the end of the summer holidays.
“And we do listen to their view – that’s why Waterworld has grown into one of the UK’s leading indoor tropical water parks.
“Twelve million satisfied visitors over our 32-year history prove the point. We are busy because we are good at what we do, and are proud to attract visitors from all over the country.”
