What Am I Doing Wrong?

[n.c2]

hi all,
i am new to fish keeping and so far not very successful i think!
i bought my young son a biorb pure 30l tank for xmas, along with it the biorb substrate, heater, plants, rocks and led light.
it has now been set up for 3 months and slowly over the time we added 6 neon tetra, 1 betta, 1 black molly, 2 platy and a dwarf frog.
everything seemed ok. my water has always been a bit cloudy but after doing some research i thought it was becaiuse the tank is relatively new. every week i change the water around 30% adding 2 tsp sera aqutan to the fresh water, hoover up the substrate, add 1 tsp sera nitivec, 1 tsp ph minus (all on recommendation from pet shop) and wash the filter sponge in old tank water. twice i have now changed the filter cartridge. i feed the fish a pinch of aquarian flakes every evening and every 2 days a frozen bloodworm cube, rinsed in tap water.
apart from the cloudy (milky) water everything seemed fine, happy fish but over the past 3 weeks we have had a couple of deaths. both the platy's and a tetra ( i replaced tetra to bring back to 6), all fish looked the same dead...no funny spots, they hadnt been eaten. i now have 6 neon tetras, 1 male betta, 1 black molly and a dwarf frog. my betta doesnt seem to have the slightest problem with any fish so im positive its not him killing them.
after the first death i bought an api master testing kit from a seller on amazon, i am a bit suspicious of this as even though the item was sealed i am not sure if its genuine. all readings appear fine and at 0 except the ammonia, that always tests as clear, as if nothing has been added to the test tube..is that strange? i think i need to fork out and buy another api kit from a pet shop, is it possible there are fakes on this!!
i have now after a death this morn decided i will do a 30% water change every other day...is this correct? i will stop buying fish until tank is stable.
also one problem i have and i hope this doesnt sound silly, the biorb gravel vaccum i bought i am not sure if using correctly. there is a lot of gunk in tank when i stir up substrate on my weekly clean. it doesnt seem to grab much of the old food etc, it just ends up sucking up loads of water, (i then panic as of course i dont want to change too much water at once)so i know lots of waste is left in tank but how do you clean properly but leave the water in??? i rang a pet shop and they just made me feel like an idiot so i am embarrassed to ask again but i have to know! is the substrate too deep, it is around 3" in places along with some biorb pebbles.
i have done lots of research on the net and i know now that biobs are hated. we dont want another tank but how can i make sure i am running this one correctly?
sorry for the long post but i just wanted to give you all as much info to get to the prob straight away. PLEASE HELP and thank you

 

[Fishy friend2]

Due to the fact of it being relatively new, and there being no nitrates the most reasonable option could be Becasue of the tank not being cycled. cycling is a proccess in which you grow bacteria that breaks down on hardul chemicals such as ammonia and nitrites.

 

[n.c2]

the ammonia readings i get is clear not even pale yello. do you think i need to buy another testing kit?
could you help me out with the gravel cleaning, thank you

 

[Cazgar]

It could be your filter isn't coping with the bioload.
Mollies aren't really suitable for a small tank as they can grow to 4", I would watch the neons with your Betta too as they can be nippy.
Don't worry about sucking up too much water, weekly changes should be around 25-30%
just remember when replacing the water that you use a dechlorinator & temperature match it as close as possible.
Remember the pet shops are there to make money & will often sell you products you really don't need.
You came to the right place to ask questions, everyone here, whether they hate biorbs or not will give you the best advice

 

[Prime Ordeal]

Have aread of this thread http/www.fishforums.net/index.php?/topic/388055-cloudy-water-issue/ which is very similar situation to yours. in particular read my response in post number 13.

In short:

You have what is most likely a bacterial bloom
You're overstocked
Your gravel is too deep, it should be no more than one inch
Your cleaning routine isn't adequate as you should hardly kick up any muck from the substrate when you disturb it.
You need to clean the substrate and the filter
You have changed filter cartridge which removes the good bacteria you want to keep.
You're using unnecessary additives, stop! Only add a dechlorinator.
When you clean the gravel you have to force the syphon right into it and of course you remove lots of water at the same time. You just top back up with dechlorinated, temperature-matched water.
The filter may not be cycled yet.
Reduce feeding to a small pinch every other day until the tank stabilises.

Probably other stuff I've overlooked in my brief look at this.

Your ammonia test should be some shade of yellow to green.

 

[n.c2]

i did wonder if there were too many fish, maybe i will give the molly back it is about 1 " at the moment. the fish all leave each other alone the betta never flares up, the tetras just swim round together and dont bother anyone else. the frog just hides all the time!
i do add dechlorinator (sera aqutan) is 1 tsp enough. the trouble is while im trying to suck up the gunk it could literally take buckets and buckets of water with it so i end up just doing it a bit, leaving lots of gunk in water but removing about 30% water, is there any other way to remove debris than this, i also try to catch large bits of dirt with a net. the water still looks filthy after a change but settles down and stays cloudy after about an hour or so.
i am appreciating this feedback and all the help you can give

 

[n.c2]

thank you prime ordeal
ok i will remove half the substrate and change water 3x per week, do you think that will help?
how many of the fish i have would you recommend is ok?

 

[fluttermoth]

You might need to do a couple of 30% changes a day until you get the gunk out of the substrate.

It'll just decompose down there and affect your water for the worse.

 

[Prime Ordeal]

i did wonder if there were too many fish, maybe i will give the molly back it is about 1 " at the moment.

Good idea if you can do that.

the fish all leave each other alone the betta never flares up, the tetras just swim round together and dont bother anyone else. the frog just hides all the time!
i do add dechlorinator (sera aqutan) is 1 tsp enough.

the trouble is while im trying to suck up the gunk it could literally take buckets and buckets of water with it so i end up just doing it a bit, leaving lots of gunk in water but removing about 30% water, is there any other way to remove debris than this, i also try to catch large bits of dirt with a net. the water still looks filthy after a change but settles down and stays cloudy after about an hour or so.

You need to remove the fish and clean the gravel out completely. Pour as much of the tank water into a bucket as you can and add a good dose of dechlorinator, transfer the fish and then remove all the substrate. Clean the substrate and any other dirty things from the tank in dechlorinated tap water. Return the gravel to the tank and refill with new dechlorinated tap water, temperature matched to the original tank water. While you're doing this gradually add dechlorinated tap water to the bucket holding the fish to acclimatise them to the new water conditions. Return the fish to the tank. You need to be very organised so that the fish aren't left in the bucket for too long.

The syphon rate will depend upon the level of the outlet compared to the inlet so, if you put the bucket or whaetever receptacle you're using to catch the water on a level with the tank, the flow will be very low. Put it lower the flow will increase.

i am appreciating this feedback and all the help you can give

thank you prime ordeal
ok i will remove half the substrate and change water 3x per week, do you think that will help?
how many of the fish i have would you recommend is ok?

You should be ok with the tetras, betta and frog as long as your maintenance is adequate.