Algae Problems With Fluctuating City Water Quality
So I just moved to a new City and setup a 75 G moderately planted Tanganyikan community tank. I have a 4 x 54 watt HOT5 light fixture but I'm currently only running 2 of the bulbs as I've been having quite a few algae problems since the setup about a month ago. I had the Initial Photo period at 10 hours but moved it up to 12 after about a week. since I've seen the algae developing I dropped it down to 9. I've been doing weekly 35 % water changes. The tank is moderately stocked and I have Eheim Pro 2 2026 for filtration.
I've tested for Nitrate, Nitrite, Ammonia and they are all in check or low. I have a Phosphate test but from what I hear they aren't the most reliable so I havent bothered with it. My Ph is reading 7.8 and the water is moderately hard.
Initially there was a bit of green water I combated with a few small 10% WC and a 4 day blackout which worked. Shortly after this short green filamentous algae started to pop up on some rocks this is when I dropped another hour on the photo period, next came some brown algae on the glass realizing something must be up I tested the water and added some phoslock to my canister as I noticed no green spot had developed at all which to my understanding is common in tanks with low P levels. Finally I've been hit with the dreaded Blue Green Cyano Bacteria. I'm doing my best to remain positive and tell myself this is just the tank getting established before the plants take off and out compete all this stuff. I've been good at cleaning the glass and plants/rocks as much as I can I try to clean the substrate in areas possible as much of the tank is rocks or shell beds. It hasn't become a major issue yet as a result of my efforts but the cyano does not seem to want to give in. I have the erythromycin handy all ready as a last resort but I'd Like to get this sorted out the natural way, by balancing this out.
The city water comes from a highly regulated river that supports a number of communities as well as locks and dams the alkalinity fluctuates from 50 to 85 mg/L. the Gh average says 90.3 mg/L but I suspect it fluctuates a lot as well. The Ph remains relatively stable at about 7.1 and nitrate never goes above 0.001 nitrite levels are never above 0.1. They give no measure of P which disappoints me I'm starting to believe this is my big problem. I contacted the local Fish shop and they told me the water here is not suited to plants but rather to African Cichlids which I explained to him I had but he said anyone with plants used R/O water. Now I know it's possible to grow plants at this PH and Hardness but I know its possible to grow the ones I currently have. Anubis and Vals have begun to shoot new leaves and runners but they are slow to grow. Bolbitis seems to have stopped growing almost. I've been thinking of adding some moss or floating plants to suck up more nutrients.
I am aware there is some kind of off balance going on maybe I need to boost up my N levels to encourage growth, or continue to drop my lighting photo period. The cyano could be caused by low N as I'm reading or a wide variety of other things. The green filamentous algae could be another sign that I have no N in the water I must be dealing with P but that's just my guess the phoslock should be doing a decent job of removing it right? I'd prefer to not use the erythromycin if possible but I have it if I have to.
75 gallon Tanganyika Community Planted