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.
The real problem is your lights. Set it to 7 hours and leave it be. Add more plants and add co2 and excel with a regular fertilizing plan.
If you want to go low tech, maybe just 1 bulb for 9 hours. T5ho outputs a good amount of light.
Do not lock up phosphates with filter inserts. Lock it up with plants.
Are you using any source of carbon? Even with only 2 bulbs, T-5HO bulbs, are quite a bit of light, and the plants will need more nutrients, including a source of carbon.
Many of the plants we use in our tanks can use the carbon from carbonates, but not all.
KH 50-85 mg/l is VERY low for Rift Lake Cichlids. I keep mine closer to 150+ mg/l (at least 9 German degrees of hardness).
GH of 90 mg/l is about half of what I would aim for.
To do water changes in my Lake Tang. tanks I run the water into a garbage can, add minerals and dechlor. then circulate it until the minerals are dissolved. I use baking soda for KH and Seachem Equilibrium or Barr's GH booster for GH.
pH in this tank runs pretty consistently in the highest 7s. GH and KH about 9 German degrees of hardness.
I do not have problems growing plants in hard water. Sure, there are a few plants that really are soft water specific, but I am not trying those in the hard water tanks. Most plants accept a very range of GH, KH and pH with no problem at all.
It's only 1.4 wpg though it would still seem relativity low light at that to me no? Yeah dropping the photo period would probably help it already seems to have. I have a pressurized CO2 system but I'd really prefer to not use it if possible or excel for that matter. I've recently begun to dose N to 5 mg/L to see if things get any better with the cyano. I also did a P test but it read 0 not that I really trust it as I know P tests can be inaccurate.
I Think I'll see a rise in both KH and GH but I agree it could be harder. There's about 100 lbs of reef rock in the tank I actually just tested to see the Kh and it was at 7 so not great still but obviously the rock is helping the tap water.
No, 1.4 wpg from T-5 HO is a lot of light. That much calls for pressurized CO2 on a tank that big.
5 ppm NO3 is the absolute lowest that I would let it get. Maintain the dosing for a week or so, and see how much the plants are using. Dose more as needed. In my low tech tanks I allow it to drop to 5 ppm because I know it is not going to hit 0 ppm too fast. In a high tech tank the plants can use 5 ppm in just a day.
Yes, P tests can be inaccurate, and there can still be enough P for the plants that are too low for the tests (hobby kits) to show. If you still want to use Phosorb use it when you are pre-treating the water for a water change. Do not allow it to hit 0 ppm, though. Plants seem to do well at any level from under 1 ppm to 5 or more ppm without triggering algae growth as long as other issues (like carbon) are under control.
Having rock that adds minerals to the water is helpful, but when you do a water change it takes a while to build up to that mineral level again. The tank goes through swings in mineral levels that are not good for the fish. Best is to alter the water before the water change, and use the rock as a way to fine tune the water between water changes.
A TDS meter might be of benefit here. When the tap water is questionable, or known to vary, this can give you more info about how variable it is.
I have a yearly water quality report from the city so I can see a lot of data but not a bunch there is a good amount of fluctuation from what I can see. TDS is not one of there listed readings but id imagine there is a good amount looking at the list of minerals present. I'm told the water here is perfect for Cichlids by many and that thats pretty much all people out here keep. I just did a WC yesterday so maybe my KH is a low reading I'll test again at the end of the week as well as GH.
I'm going to keep the nitrates up and see how that goes before I figure out if CO2 is really necessary to keep the algae at bay.
As far as the phoslock goes I only used it because of the initial green water blooms as a test to see how the tank would react to lower P levels.
I'm starting to feel If I reduce the photo period and keep N levels up as well as introduce some more plants I can combat this.
Ah, the watts per gallon rule. Forget that rule for anything that's not a t-8 bulb.
I have understood the inherent flaws of using it as a rule for a while now which is why I prefer to use it as a ballpark figure. All I mean is that I wouldn't have considered this a high light tank by any means, maybe moderate at most.
I just ordered a few more plants to help with nutrient uptake so I'm going to keep on track with a couple of things.
a) keep up with the removal of cyano
b) keep N above 5 mg/L
c) reduce photo period
d) add more plants
e) keep up with WC if anything do more
f) last resort add CO2
Now I'm dosing N should I be considering dosing K or P at this point as well, or maybe just K considering at this point I'm assuming the P levels are already moderate?
Now try using the wpg rule on LED. You'll get scorched plants.
Haha that's quite true, however I always just assumed for florescent tubes the wpg rule could be used as a guideline, while for other methods like MH, SV, PC and LED it was obviously not functional. It's good to know its not really good for anything but the larger diameter Florescent's.
I contacted the city water lab today apparently they don't test P but got me a 2012 record of a test done by environment Canada reading 0.01 mg/L This means little to me though as obviously once a year test in a river is not a reliable number to go by.
I've been looking at silicates and algae growth and I remembered something about silicates in the water quality report I read earlier. Turns out Sodium Silicate is dosed and reads anywhere from 2.3-20.2 mg/L could this be my problem ?
Well, the gist of the comments from everybody is it's your light, nothing to do with your tap water, silicates and what not. You need to lower your lights or add CO2, and add fertilizers including phosphates. Plants need them to live.
The silicates could have contributed to the "brown algae on glass" (diatoms)
I believe it has lots to with the tap water, I agree the lighting might not be optimal but there is more going on than that. I'm told by the lfs manager who's been breeding Cichlids in this water or years told me anyone who has a non planted tank has cichlids or community on single tubes with low photo periods to prevent algae. He also said anyone with plants uses RO water because the city's water isn't good to grow them and the parameters fluctuate too much. I want to attempt to address this issue first, furthermore in the previous city that I lived in the water was much more stable and in tanks with more light than this and no CO2 including this one I had far less to no issues with algae as long as regular maintenance and proper nutrient levels were present.
Happy water hunting.
I would start with this:
Add pressurized CO2. Set a steady level, so it is really consistent. This might take a week or two. You want the CO2 to be fairly high, but do not gas the fish.
Decide what parameters you will aim for in the tank water.
Ammonia = 0 ppm
Nitrite = 0 ppm
Nitrate = between 5-20 ppm
...and so on. Set ranges that are suitable to your livestock.
Start a record. Test the tap water at least once a week and record:
Ammonia, NO2, NO3
All other tests you have.
When the water from the city looks the best, do as large a water change as you need to, and think about storing a barrel (perhaps a 50 gallon drum) of that 'best water' to be ready for another water change or 2.
When the water from the city is bad, but you absolutely have to do a water change then use as much RO as you can, and as little city water as you can. Add minerals to the RO water to make it match the GH etc. that you are aiming for.
Look into ways to pre-treat the city water to even it out and get rid of whatever things it has that you do not want in the tank.
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