Aquarium fish tank help

[nappyzoneloveschinesefood]

Dh has just got a new fish tank as a starter - we got this aquastart aquaone 500 (just keeping cold water thingys) like this. Anyhow on the box itt says it comes with undergravel filtration and in the instructions but then in the box which was sealed was no undergravel filtration pad whatever one of them is but a maxi102f internal filter. Have we been diddled or is this better any fish experts??? Dh thiks it will do the job but i think he just saying that coz he excited to get it going.

My DP keeps a marine tank and he said that the internal filter will do the same job as the undergravel filter, just remember when cleaning filter sponge/media rinse it in tank water and not fresh water as this preserves the bacteria. Also, take it slowly when adding new fish i.e. not too many at once to allow the filter to get used to the waste etc..

Thanks for that