Dangers of ancient substrate?
Substrate is about 2 years old, aquarium gravel.
Enormous amounts of mulm from top to bottom, and virtually undisturbed apart from the odd vacuum around the plants.
Apart from aesthetics, does there come a point where there is an excess of organic matter in the substrate, thus offsetting any nutritional benefit for the plant?
I have no nitrate excess problem.
I wanna know....to
Research 'Old Tank Syndrome'.
Here is something I wrote on this subject for people with fish-only tanks. It probably does not directly answer your question, but does provide more info to consider when you are deciding what to do.
If you want to keep that gravel, but improve conditions in the tank, I would start vacuuming it a little bit at a time, until (perhaps a couple of months from now) it is clean.
OLD TANK SYNDROME
Aquariums with less than optimum water changes will accumulate toxins that can poison the fish, shrimp, snails and plants. As nitrate climbs and the decomposing bacteria use up the minerals in the tank the pH can drop, to 6.0 and lower. Nitrospira bacteria (the actual nitrifying bacteria) do not do well at lower pH and may be dead. Ammonia climbs, pH drops, nitrate may be very high. The GH may be quite high if the tank has just been topped off using tap water.
The fish might have adapted to the high nitrate. Those that could not adapt have died. If you try adding new fish, they die. The low pH is keeping the ammonia in the NH4+ form, which is less toxic Any water changes create changes in the GH, KH and pH levels and the fish become sick or die.
This tank is suffering from Old Tank Syndrome. The best, safest cure is a long, slow change back to optimum conditions. The fish have been living like this long enough to adapt to the low GH, KH and pH as well as the high nitrate. An instant change back to 'perfect' would be too much for them.
Here is what I would do: (and why)
1) 10% daily or even twice daily water changes. Use a dechlorinator that locks up ammonia, nitrite and nitrate. Prime, Amquel Plus... (Any larger water change creates too big a water chemistry change)
2) Zeolite in the filters. Get 3 bags: every day swap out one bag and rejuvenate it overnight in salty water, then soak in fresh water (RO or Distilled is best) You will always have 2 bags in the tank, and one in rejuvenation. (Zeolite removes ammonia, but gets filled up. It is cheapest to buy a large jar of it and cut up some nylon stockings as bags.)
3) If there is over 1.5 watts of light add all the plants you can. Fast growing stuff like Anacharis is best. (Plants are the fastest ammonia removers. But under 1.5 watts they are more likely to rot than to help. If fish eat them, not to worry, just feed the fish less. Plants are low nitrogen compared to high protein fish food, thus contributing less ammonia waste to the problem)
4) Deep and thorough gravel vac as much as you can this week. (Decomposing gunk is lowering the pH and contributing to ammonia problem) 10% water change does not allow for much gravel vacuuming in any one session, but you can get over the whole tank bottom at least once this week.
5) Order Nitrospiros species of nitrifying bacteria. Microbe Lift’s Nite Out II, Tetra Safe Start and Dr. Tim’s One and Only are good. Do not waste your money on any other source of ‘bacteria in a bottle’. Wrong ingredients. Other sources of ntrifying bacteria include other healthy, cycled tanks. You could add some floss or sponge filter media from a healthy tank to this ailing tank, but the bacteria will not grow very well in such low pH. I would not add it this week. Do not take so much filter media from the established, healthy tank that it gets into trouble. These bacteria will not do very well when the pH is too low, but as soon as the pH has climbed to 6.5, add whatever source of bacteria you can to boost the population in the tank.
6) Feed less. Half what was fed before. Feed low protein foods if the fish can handle them. (This is the Garbage In = Garbage Out principle. Less GI = less GO.)
7) Clean the filter in water removed from the tank. Tap water with chloramines or chlorine can kill whatever nitrifying bacteria may be alive.
By the end of the first week the ammonia will be significantly lower, the pH slightly higher, nitrite might be showing and nitrate might still be very high. Gravel is much cleaner. O2 levels are rising, benefiting fish and nitrifying bacteria. If the tests show nitrite, add sodium chloride (salt) @ 1 teaspoon per 20 gallons of water. Add this much whenever you do a water change based on the amount of the water change. If you do a 5 gallon water change add .25 teaspoon to the new water. Keep this up until the nitrite level consistently reads 0 ppm.
1) Do daily 20% water changes, and deep gravel vacs. Also, clean the filter. (The larger water changes are going to be altering the pH a bit more, but are removing a lot more nitrate. As the nitrifying bacteria get going again removing nitrate is very important.)
2) Add nitrifying bacteria. If you use a bottled product then no more gravel vacs the rest of the week, and no water changes for a couple of days. Do not clean any filter for a week. (Allow the bacteria to settle in the filters and gravel without removing it or knocking it off the gravel or filter media.) If you were able to get cycled media from a healthy tank then keep up the water changes and gravel vacs.
3) Continue swapping out the zeolite bags, but if the ammonia tests show that the ammonia is a lot lower, just swap out one bag every other day. (The nitrifying bacteria need ammonia to eat. By removing it with zeolite you are starving the bacteria. It takes several days for the bacteria to settle in and really get going on the ammonia, though, so keep the zeolite going this week. Might still need daily replacement)
4) Continue feeding the fish significantly less food. If they will eat vegetables or plants this is better.
After the second week I will expect the ammonia to be gone or almost gone. The nitrifying bacteria might be having a hard time. Be patient. It will get going soon. The pH may not be the same as the tap water yet, but it is OK if it is a little higher with the ammonia getting so low. Continue using a water conditioner that locks up ammonia, nitrite and nitrate so the fish are protected.
1) Clean the filter. Be very gentle, the nitrifying bacteria population is still establishing itself.
2) Continue with daily water changes, but if the pH, GH and KH are closer to the tap water then increase them to 25%.
3) Resume deep gravel vacs (if you had stopped because of adding bottled bacteria).
4) Decrease the use of zeolite. Monitor the ammonia. If the plants and bacteria are handling the ammonia, then stop using zeolite. If the plants and bacteria are not up to it yet, keep using the zeolite, but perhaps only swap out the bags a couple of times this week. (The zeolite can only be rejuvenated just so many times, then is too plugged up with stuff that cannot be removed. Monitor the ammonia, and change out the zeolite bags, but remember there are other things removing the ammonia, too. It might be that the zeolite is dead, and it is time to throw it away)
By the end of week three the aquarium is likely getting back into shape. pH is much closer to the tap water pH (and KH and GH are matching the tap, too). Nitrifying bacteria and plants ought to be handling all or almost all the ammonia. You might be seeing nitrite. If nitrite shows then add 1 teaspoon of salt per 20 gallons of water. Nitrate may still be too high, (though a lot lower than 3 weeks ago). The nitrifying bacteria will be creating more nitrate as they establish themselves. Plants will be very helpful here by removing ammonia before it even gets to the bacteria.
If the pH, KH and GH of tap and tank match then do as large a gravel vac and water changes as needed to really get the nitrates down.
Goal: Ammonia and Nitrite will ultimately read 0 ppm, but if the tank is still cycling try to keep the ammonia < .25 ppm, and the nitrite under 1 ppm.
Try to get and keep the nitrate under 20 ppm. Lower is better.
If the tap water pH, GH and KH are not close enough to the tank to permit larger water changes then do more frequent ones, perhaps 30% daily. It is also a good idea to keep up the deep gravel vacs to continue removing debris.
Eliminate zeolite. (Now that the bacteria is getting back to where it should be you do not need this emergency removal product, the bacteria are doing the work.)
Offer the fish a little more food if they really need it, but people who allow a tank to reach this condition are often over feeding anyway. Perhaps the new diet really is better. If your fish do need a higher protein diet, more bugs, worms, shrimp and other meaty foods add these back slowly and monitor the ammonia, nitrite and nitrate levels.
Set up a schedule of weekly water changes. This might be 25% once or twice a week. If the tap water and the tank water have similar water chemistry then you can do larger water changes. Clean the filter regularly. Vacuum the floor of the tank.
Feed the fish a varied diet, making sure they eat all the food. Fast them one day per week.
Test the water weekly. Optimum readings are:
Ammonia 0 ppm. Any other result is an emergency.
Nitrite 0 ppm. Any other result is an emergency.
Nitrate < 20 ppm. If it gets higher than this you will need to do more frequent or larger water changes.
GH, KH and pH ought to be stable, not changing from week to week.
Top off with Distilled or Reverse Osmosis water.
thanks diana, much appriciated!
Can you push a finger through the substrate all over the tank? The only time I went through the substrate and completely vacuumed it out was due to some sort of fungal/root/decomposition/algal growth that bound the substrate so tightly I couldn't push my finger through it. Weird experience and haven't seen it since.
Mostly I leave the bottom alone but keep the top part clean looking. When I change tanks I have the old tank partly filled so when I transfer the substrate some mulm is rinsed off but it is still very 'dirty'. The 100 gallon tank's substrate was at least 5 years old when I transferred it to the 180 gallon tank and there wasn't as much mulm as I thought and that old substrate was sweet smelling like good earth.
I haven't rinsed old substrate clean since 2000.
If you have the rescape itch then do take out all the plants and fish and any other critters, mix up the substrate and drain all the water out, rescape and plant, fill part way and dump that water as you vacuum the surface then slowly refill so the water stays clear. That would remove a lot of the mulm but not all of it.
That written, if you don't have plant growth or algal issues then you are probably just fine. I wouldn't call that old substrate yet.
But there is a big difference between a tank which has not been properly maintained (i.e. regular water changes and healthy plant growth with nutrients added as needed) and a tank that HAS been maintained properly, but has an old substrate. Below is a link to a tank that I just stripped down, not because the fish weren't healthy (I regularly pulled bags of Cherry Barbs out of this tank to sell to the LFS) and not because the plant growth wasn't good. (you can see that in the photo). I am getting rid of the tank because it is over 30 years old, and I am worrying about the silicone seals.
The tank has been set up with the current substrate (1-3mm quartz gravel plus laterite, a handful of peat, and, of course, by now, LOTS of mulm and organic material from the plants themselves) for about 20 years.
Over that time, probably about 4 times, I loosened the substrate by removing the plants from about 1/3 of the tank at a time, gravel vacuuming that section, and replanting. I did 1/3 per month until the whole tank was done, and it was good to go for several more years. (this is a technique taught to me by Claus Cristensen of Tropica).
Just wanted to show that tanks with a good substrate can be very successful for a VERY long time!
Isn't it interesting that we believe that MTS, which is based on dirt or unknown composition, is "good", but, old substrate, which has miscellaneous organic stuff mixed in, leaving a substrate of unknown composition, is "bad". Personally, I think if I can stir up the substrate a bit and it stinks bad, it is "bad", but if it doesn't stink, it is "good".
I have a single tank that has the same substrate (without deep cleaning) >30yrs wet. I've added finer grain material in a layer to increase the depth a couple times once I added plants to my tanking but the original river gravel still sits on top of decades old and unused UG filter plates. :icon_eek:
I use it as a breeding tank.
Get some malaysian trumpet snails if you are concerned about it. 2 years is nothing, though.
I just logged on to ask how often people completely tear down and redo their tanks for exactly this reason. I have a 55 gallon tank with miracle gro organic potting mix topped with eco-complete. It is just about a year old and moderately planted with not very many fish. I'm redoing mine this week for a few reasons:
1- I was worried about the organic matter in the substrate
2- I was worried the plants had used up all of the nutrients in the soil/eco-complete
3- I want to do a major rescaping of the plants
So based upon what I've read here, one year is not a long time with healthy plants and regular water changes?
Eco complete absorbs and then releases nutrients to plants. It has no nutrients to run out of. If you plant some stems that need some extra oomph, add some root tabs. Otherwise, you should be fine with what you have. Now, if you want a new look and a totally new scape, go for the tear down. I do not think you are forced to do it, however.
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I think what you have now is potentially a fantastic super substrate and potentially a dangerous breeding ground for the new black plague. Sterile can be good... organic can be good...Who knows?!? I believe there is such a thing as too much dissolved organic matter in the water column, which you may be getting, but in the substrate...It's an interesting question for sure.
I think my tank has old tank syndrome, has been setup for ~4 yrs, 55 gal. I am trying to figure how to increase the pH. It's currently at 4.5-4.9. Added 4 - 6 cups of coral in wet/dry and over 48 hrs, has not changed. Ammonia, nitrate, nitrite all reading at 0. It's probably 50% covered with plants. When I noticed the low pH last month, tried vacuuming gravel when doing a WC, but then noticed the ammonia went up, so figured I must be getting rid of good bacteria, so this current time around, only removed water not via gravel, but pH did not increase. Fishes currently in there are 29 cardinals (1+ inches), 5 pristellas, 6 rasboras, 2 3" clown loaches, 5" bristlenose, newly added panda cories (did lose 3 out of 8). Healthiest are the tetras. Nothing is really listless, loaches were, but now have their colors back.
So, my questions are: do water change via vacuuming gravel or only water at mid-level? Add additional coral until I see start of increase in pH?
Thanks for inputs.
FunkyFish, read Diana's post, the third one down. It's pretty detailed and looks like a good way to go about it. that should minimize the risk to your livestock and plants.
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