Excessive Algae & High PH & Nitrate.. HELP!

Hi Guys,

Hope you are all well (hopefully I am posting this in the correct place).

I'm about 6 months into tropical fishkeeping and am now having issues with my tank so would love some advice from other passionate members of the community (as it's worrying me every day haha)!

I lost my Betta a few weeks back and am worried about the health of some other fish. The algae build up in my tank seems excessive, with my ornaments/filter/glass noticably green a few days after my weekly water changes. I have carried out a PH, Ammonia, Nitrite and Nitrate test today for the first time. The PH level and Nitrate levels are at the maximum - picture at end of thread (I was pleased to see Ammonia and Nitrite seem fine though).

Everything I have read leads back to water issues, which in turn leads me to the filter, but would love to hear the thought of you guys in the community who know better than me!

Some final other notes about my fishkeeping/tank:

- I have a 110L tropical tank with an Aqua Moray 700 Filter. The temperature is set to 27 degrees C.
- I have 3 small plecos, 6 neon tetras, 4 balloon mollys, 4 guppys, 2 small corydoras and feed them a pinch of food daily and one wafer daily (broken into 4 parts).
- I carry out weekly water change (approx 30-50%) using Tapsafe and currently average a fortnightly filter clean.

Would love some advice so what would you recommend?

Thanks
Evan

There are a number of issues some pertaining to stock and others to compatibility.
Find the GH or general hardness of your tank. Live bearing fish like guppies and mollies require " hard water" which is usually from 8-20 Degrees general hardness. Hardness is the measurement of calcium and magnesium in water tetras like neons require a "soft water" from 0-6 degrees. Hardcwater fish wont do well in soft watee and soft water fish not well in hard water. Fibd out your source water DGH " hardness" and put the fish in it that are compatible with that water and rehome the others.
Secondly 3 plecos in one tank is way to many. Not only are plecos territorial but they are extremely messy fish that eat alot creating a lot of waste that in turn creates ammonia. And depending on the pleco sone like the common pleco can get 2 feet. If its a dwarf pleco like a bristlenose or rubber lipbor clown pleco they wont exceed more than 6 inches but still should be kept alone and are still messy fish.
As for cloudy water and algae. Cloudy water is most likely an ammonia or nitrate spike or a bacterial bloom. Either way do a 75% water change and to decrease algae decrease light. Algae needs 8 hours of continuous light to thrive plants dont. Decrease the time the lights are on to under 8 hours. Secondly decrease feeding. Food leads to waste and the nutrients feed algae if one is feeding twice a day go to once if once go every other day. Decreased lighting and decreased nutrients will decrease algae. Also adding fast growing plants will take up excess nutrients from algae.

Agree with above. Additionally, have you tested the tap water for nitrates? It is important to ascertain if any of the nitrates (it is way too high for any fish long term) come in with the tap water, or are solely occurring within the system.

Can you test your tap water for both pH and high range pH - and leave a glass of water to stand for 24 hours then test with them both again.

If the pH is over 7.6 the 'ordinary range' pH will show the highest number on the chart regardless of how high it really is so you need to check with the high range pH tester to see if it actually 7.6 or higher.
It is always a good idea to test tap water to see if the tank is the same or something in the tank is changing things. And the reason for testing water that's been allowed to stand is to allow gases or any additive added by the water supplier to gas off as this can change the pH.